stat 200, final (chapters 6-12)

which of the following is not a requirement in determining whether there is a linear correlation between the two variables? a. the sample of paired data is a simple random sample of quantitative data b. any outliers must be removed if they are known to be errors c. a scatterplot should visually show a straight-line pattern d. if r > 1, then there is a positive linear correlation

d. if r > 1, then there is a positive linear correlation

which of the following is not a property of the linear correlation coefficient r? a. the value of r is always between -1 and 1 inclusive b. the value of r is not affected by the choice of x or y c. the value of r measures the strength of a linear relationship d. the linear correlation coefficient r is robust. that is, a single outlier will not affect the value of r.

d. the linear correlation coefficient r is robust. that is, a single outlier will not affect the value of r.

which of the following is not a requirement for testing a claim about a population mean with σ known? a. the sample is a simple random sample b. the value of the population standard deviation is known c. either the population is normally distributed or n >30 or both d. the sample mean, x with a bar over it, is greater than 30

d. the sample mean, x with a bar over it, is greater than 30

which of the following is not a requirement of testing a claim about two population means when σ1 and σ2 are unknown and not assumed to be equal? a. the two samples are independent b. either the two sample sizes are large (n1>30 and n2>30) or both samples come from populations having normal distributions, or both of these conditions are satisfied c. both samples are simple random samples d. the two samples are dependent

d. the two samples are dependent

two samples are ______ if the sample values are paired

dependent

a _______ is a procedure for testing a claim about a property of a population

hypothesis test

a researcher collects a simple random sample of grade-point averages of statistics students, and she calculated the mean of this sample. under what conditions can that sample mean be treated as a value from a population having a normal distribution?

if the population of grade-point averages has a normal distribution and the sample has more than 30 grade-point averages

two samples are _____ if the sample values from one population are not related to or somehow naturally paired or matched with the sample values from the other population

independent

paired sample data may include one or more __________, which are points that strongly affect the graph of the regression line

influential points

the _____ measures the strength of the linear correlation between the paired quantitive x- and y-values in a sample

linear correlation coefficient r

a normal distribution is informally described as a probability distribution that is "bell-shaped" when graphed. draw a rough sketch of a curve having the bell shape that is characteristic of a normal distribution

looks like a rollercoaster, incline at the bottom that goes into an upside-down u-shape.

a newspaper provided a "snapshot" illustrating poll results from 1910 professionals who interview job applicants. the illustration showed that 26% of them said the biggest interview turnoff is that the applicant did not make an effort to learn about the job or company. the margin of error was given as +-3 percentage points. what important feature of the poll was omitted?

the confidence level

what does the notation z subscript α indicate?

the expression z subscript α denotes the z score with an area of α to its right

what is the difference between the following two regression equations? y^ = b0 +b1x y= β0 + β1x

the first equation is for sample data; the second equation is for a population

find the indicated z score. the graph depicts the standard normal distribution with mean 0 and standard deviation 1. the area of the shaded region, to the left, is 0.3015

the indicated z score is -0.52

find the indicated z score. the graph depicts the standard normal distribution with mean 0 and standard deviation 1. the area of the shaded region, to the right, is 0.8708

the indicated z score is -1.13

find the indicated z score. the graph depicts the standard normal distribution with mean 0 and standard deviation 1. the area of the shaded region, to the right, is 0.2061

the indicated z score is 0.82

what requirements are necessary for a normal probability distribution to be a standard normal probability distribution?

the mean and standard deviation have the values of µ = 0 and σ = 1

assume that a randomly selected subject is given a bone density test. those test scores are normally distributed with a mean of 0 and a standard deviation of 1. find the probability that a given score is less that -1.81 and draw a sketch of the region

the probability is 0.0351. the sketch is bell-shaped with the area to the left shaded at the -1.81 mark, to show that it is less than -1.81

using the lengths (in.), chest sizes (in.), and weights (lb) of bears from a data set, a researcher gets the regression equation below. weight = -274 + 0.426 length + 12.1 chest size identify the response and predictor variables in this regression equation

the response variable is weight and the predictor variables are length and chest size

assume that adults have iq scores that are normally distributed with a mean of 101.9 and a standard deviation of 16.1. find the probability that a randomly selected adult has an iq greater than 133.3

0.0256

a genetic experiment with peas resulted in one sample of offspring that consisted of 411 green peas and 160 yellow peas. construct a 95% condience interval to estimate of the percentage of yellow peas. it was expected that 25% of the offspring would be yellow. given that the percentage of offspring yellow peas is not 25%, do the results contradict expectations?

0.243 < p < 0.317 no, the confidence interval includes 0.25, so the true percentage could easily equal 25%

the waiting time between a subway departure schedule and the arrival of a passenger are uniformly distributed between 0 and 6 minutes. find the probability that a randomly selected passenger has a waiting time greater then 3.25 minutes

0.458

the waiting time between a subway departure schedule and the arrival of a passenger are uniformly distributed between 0 and 5 minutes. find the probability that a randomly selected passenger has a waiting time less then 3.75 minutes

0.75

find the indicated critical value of z subscript 0.07

1.48

find the critical value z subscript α/2 that corresponds to the confidence level 90%

1.65

engineers want to design seats in a commercial aircraft so that they are wide enough to fit 95% of all males. (accommodating 100% of males would require very wide seats that would be much too expensive.) men have hip breadths that are normally distributed with a mean of 14.7 in. and a standard deviation of 1.2 in. find p subscript 95. that is, find the hip breadth for men that separates the smallest 95% from the largest 5%

16.7 in.

find the critical value z subscript α/2 that corresponds to the confidence level 98%

2.33

about _______% of the area is between z=-1 and z=1 (or within 1 standard deviation of the mean)

68.27%

about _______% of the area is between z=-2 and z=2 (or within 2 standard deviations of the mean)

95.45%

about _____% of the area is between z=-3 and z=3 (or within 3 standard deviations of the mean)

99.75%

a ______ exists between two variables when the values of one variable are somehow associated with the values of the other variable

correlation

in a study of 800 randomly selected medical malpractice lawsuits, it was found that 512 of them were dropped or dismissed. use a 0.05 significance level to test the claim that most medical malpractice lawsuits are dropped or dismissed.

H0: p = 0.5; H1: p > 0.5

a magazine provided results from a poll of 1500 adults who were asked to identify their favorite pie. among the 1500 respondents, 13% chose chocolate pie, and the margin of error was given as +-3 percentage points. given specific sample data, which confidence interval is wider: the 90% confidence interval or the 80% confidence interval? why is it wider?

a 90% confidence interval must be wider than an 80% confidence interval in order to be more confident that it captures the true value of the population proportion

if you are asked to find the 85th percentile, you are being asked to find ______

a data value associated with an area of 0.85 to its left

what conditions would produce a negative z-score?

a z-score corresponding to an area located entirely in the left side of the curve

in a science fair project, emily conducted an experiment in which she tested professional touch therapists to see if they could sense her energy field. she flipped a coin to select either her right hand or her left hand, and then she asked the therapists to identify the selected hand by placing their hand just under emily's hand without seeing it and without touching it. among 295 trials, the touch therapists were correct 140 times. complete parts (a) through (d) a. given that emily used a coin toss to select either her right hand or her left hand, what proportion of correct responses would be expected if the touch therapist made random guesses? b. using emily's sample results, what is the best point estimate of the therapist' success rate? c. using emily's sample results, construct a 90% confidence interval estimate of the proportion of correct responses made by touch therapists d. what do the results suggest about the ability of touch therapists to select the correct hand by sensing energy fields?

a. 0.5 b. 0.475 c. 0.427 < p < 0.522 d. since the confidence interval is not entirely above 0.5, there does not appear to be sufficient evidence that touch therapists can select the correct hand by sensing energy fields

which of the following is not an equivalent expression for the confidence interval given by 161.7 < µ < 189.5? a. 161.7+-27.8 b. (161.7, 189.5) c. 175.6-13.9 < µ < 175.6+13.9 d. 175.6+-13.9

a. 161.7+-27.8

consider a drug that is used to help prevent blood clots in certain patients. in clinical trials, among 5980 patients treated with this drug, 147 developed the adverse reaction of nausea. use a 0.5 significance level to test the claim that 3% of users develop nausea. complete parts (a) through (e) a. identify the null and alternative hypotheses b. identify the test statistic c. identify the p-value d. identify the conclusion e. does nausea appear to be a problematic adverse reaction?

a. H0: p = 0.03; H1: p =/ 0.03 b. test statistic = -2.46 c. p-value = 0.014 d. reject H0. there is sufficient evidence to warrant rejection of the claim that 3% of users develop nausea e. since the rate of nausea appears to be relatively low, it is not a problematic adverse reaction

in a study of the accuracy of fast food drive-through orders, one restaurant had 34 orders that were not accurate among 393 orders observed. use a 0.10 significance level to test the claim that the rate of inaccurate orders is equal to 10%. complete parts (a) through (e) a. identify the null and alternative hypotheses b. identify the test statistic c. identify the p-value d. identify the conclusion e. does the accuracy rate appear to be acceptable?

a. H0: p = 0.1; H1: p = /0.1 b. test statistic = -0.89 c. p-value = 0.373 d. fail to reject H0. there is not sufficient evidence to warrant rejection of the claim that the rate of inaccurate orders is equal to 10% e. since there is not sufficient evidence to reject the claim that the rate of inaccurate orders is equal to 10%, it is plausible that the inaccuracy rate is 10%. this rate would be too high, the restaurant should work to lower the rate

suppose 217 subjects are treated with a drug that is used to treat pain and 54 of them developed nausea. use a 0.05 significance level to test the claim that more than 20% of users develop nausea. complete parts (a) through (d) a. identify the null and alternative hypotheses b. identify the test statistic c. identify the p-value d. identify the conclusion

a. H0: p = 0.20; H1: p > 0.20 b. test statistic = 1.80 c. p-value = 0.036 d. reject H0. there is sufficient evidence to warrant support of the claim that more than 20% of users develop nausea

assume that adults were randomly selected for a poll. they were asked if they "favor or oppose using federal tax dollars to fund medical research using stem cells obtained from human embryos." of those polled, 486 were in favor, 398 were opposed, and 118 were unsure. a politician claims that people don't really understand the stem cell issues and their responses to such questions are random responses equivalent to a coin toss. exclude the 118 subjects who said that they were unsure, and use a 0.01 significance level to test the claim that the proportion of subjects who respond in favor is equal to 0.5. complete parts (a) through (e) a. identify the null and alternative hypotheses b. identify the test statistic c. identify the p-value d. identify the conclusion e. what does the result suggest about the politician's claim?

a. H0: p = 0.5; H1: p =/ 0.5 b. test statistic = 2.96 c. p-value = 0.003 d. reject H0. there is sufficient evidence to warrant rejection of the claim that the responses are equivalent to a coin toss e. the result suggests that the politician is wrong in claiming that the responses are random guesses equivalent to a coin toss

in one study of smokers who tried to quit smoking with nicotine patch therapy, 37 were smoking one year after treatment and 34 were not smoking one year after the treatment. use a 0.10 significance level to test the claim that among smokers who try to quit with nicotine patch therapy, the majority are smoking one year after the treatment. complete parts (a) through (e) a. identify the null and alternative hypotheses b. identify the test statistic c. identify the p-value d. identify the conclusion e. do these results suggest that the nicotine patch therapy is not effective?

a. H0: p = 0.5; H1: p > 0.5 b. test statistic = 0.36 c. p-value = 0.361 d. fail to reject H0. there is insufficient evidence to warrant support of the claim that the majority are smoking one year after the treatment e. since there is sufficient evidence to support the claim that the majority are smoking one year after the treatment, there is insufficient evidence to suggest that the nicotine patch is not effective

in a test of the effectiveness of garlic for lowering cholesterol, 49 students were treated with raw garlic. cholesterol levels were measured before and after the treatment. the changes (before minus after) in their levels of LDL cholesterol (in mg/dL) have a mean of 0.9 and a standard deviation of 21.7. use a 0.01 significance level to test the claim that with garlic treatment, the mean change in LDL cholesterol is greater than 0. assume that a simple random sample has been selected and complete parts (a) through (d) a. identify the null and alternative hypotheses b. identify the test statistic c. identify the p-value d. identify the conclusion

a. H0: µ = 0; H1: µ > 0 b. test statistic = 0.29 c. p-value = 0.386 d. fail to reject H0. there is not sufficient evidence to conclude that the mean of the population of changes is greater than 0

a data set includes data from 400 random tornadoes. the display from technology available below results from using the tornado lengths (miles) to test the claim that the mean tornado length is greater than 2.5 miles. use a 0.05 significance level to complete parts (a) through (d) a. identify the null and alternative hypotheses b. identify the test statistic c. identify the p-value d. identify the conclusion

a. H0: µ = 2.5; H1: µ > 2.5 b. test statistic = 2.38 c. p-value = 0.009 d. reject H0. there is sufficient evidence to support the claim that the mean tornado length is greater than 2.5 miles

a data set lists earthquake depths. the summary statistics are n = 600, x with a bar over it = 4.35 km, s = 4.51 km. use a 0.01 significance level to test the claim of a seismologist that these earthquakes are from a population with a mean equal to 4.00. assume that a simple random sample has been selected and complete parts (a) through (d) a. identify the null and alternative hypotheses b. identify the test statistic c. identify the p-value d. identify the conclusion

a. H0: µ = 4.00; H1: µ =/ 4.00 b. test statistic = 1.90 c. p-value = 0.058 d. fail to reject H0. there is not sufficient evidence to conclude that the original claim that the mean of the population of earthquake depths is 4.00 km is not correct

the display provided from technology available below results from using data for a smartphone carrier's data speeds at airports to test the claim that they are from a population having a mean less than 5.00 mbps. conduct the hypothesis test using these results. use a 0.05 significance level to complete parts (a) through (d) a. identify the null and alternative hypotheses b. identify the test statistic c. identify the p-value d. identify the conclusion

a. H0: µ = 5.00; H1: µ < 5.00 b. test statistic = -0.22 c. p-value = 0.415 d. fail to reject H0. there is not sufficient evidence to support the claim that the sample is from a population with a mean less than 5.00 mbps

a data set about speed dating includes "like" ratings of male dates made by the female dates. the summary statistics are n= 194, x with a bar over it = 6.55, s = 2.06. use a 0.01 significance level to test the claim that the population mean of such ratings is less than 7.00. assume that a random sample has been selected and complete parts (a) through (d) a. identify the null and alternative hypotheses b. identify the test statistic c. identify the p-value d. identify the conclusion

a. H0: µ = 7.00; H1: µ < 7.00 b. test statistic = -3.04 c. p-value = 0.001 d. reject H0. there is sufficient evidence to conclude that the mean of the population of ratings is less than 7.00

assume a significance level of α = 0.1 and use the given information to complete parts (a) and (b). original claim: the standard deviation of pulse rates of a certain group of adult males is more than 12 bpm. the hypothesis test results in a p-value of 0.2214 a. state a conclusion about the null hypothesis b. without using technical terms, state a final conclusion that addresses the original claim

a. fail to reject H) because the p-value is greater than α b. there is not sufficient evidence to support the claim that the standard deviation of pulse rates of the group of adult males is more than 12 bpm.

assume a significance level of α = 0.05 and use the given information to complete parts (a) and (b). original claim: more than 59% of adults would erase all of their personal information online if they could. the hypothesis test results in a p-value of 0.1536 a. state a conclusion about the null hypothesis b. without using technical terms, state a final conclusion that addresses the original claim

a. fail to reject H0 because the p-value is greater than α b. there is not sufficient evidence to support the claim that the percentage of adults that would erase all of their personal information online if they could is more than 59%

which of the following is not a commonly used practice? a. if the distribution of the sample means is normally distributed, and n > 30, then the population distribution is normally distributed b. if the original population is normally distributed, then for any sample size n, the sample means will be normally distributed c. the distribution of sample means gets closer to a normal distribution as the sample size gets larger d. if the original population is not normally distributed and n > 30, the distribution of the sample means can be approximated reasonably well by a normal distribution

a. if the distribution of the sample means is normally distributed, and n > 30, then the population distribution is normally distributed

a certain drug is used to treat asthma. in a clinical trial of the drug, 17 of 262 treated subjects experienced headaches (based on data from the manufacturer). the accompanying calculator display shows results from a test of the claim that 11% of treated subjects experienced headaches. use the normal distribution as an aproximation to the binomial distribution and assume a 0.05 significance level to complete parts (a) through (e) a. this is a ____ test b. what is the test statistic?

a. left-tailed test b. z = c. d. e.

assume a significance level of α = 0.1 and use the given information to complete parts (a) and (b). original claim: the mean pulse rate (in beats per minute) of a certain group of adult males is 70 bpm. the hypothesis test results in a p-value of 0.0019 a. state a conclusion about the null hypothesis b. without using technical terms, state a final conclusion that addresses the original claim

a. reject H0 because the p-value is less than or equal to α. b. there is sufficient evidence to warrant rejection of the claim that the mean pulse rate (in beats per minute) of the group of adult males is 70 bpm

which of the following is not a requirement for constructing a confidence interval for estimating a population mean with σ known? a. the confidence level is 95% b. the sample measures a quantitative value c. the sample is a simple random sample d. either the population is normally distributed or n > 30, or both

a. the confidence level is 95%

which of the following is not a requirement for testing a claim about a population with σ not known? a. the population mean, µ, is equal to 1 b. either the population is normally distributed or n > 30 or both c. the sample is a simple random sample d. the value of the population standard deviation is not known

a. the population mean, µ, is equal to 1

which of the following is not a requirement for constructing a confidence interval for estimating the population proportion? a. the trials are done without replacement b. there are at least 5 successes and 5 failures c. there are a fixed number of trials d. the sample is a simple random sample

a. the trials are done without replacement

which of the following is not true of the confidence level of a confidence interval? a. there is a 1 - α chance, where α is the complement of the confidence level, that the true value of p will fall in the confidence interval produced from our sample b. the confidence level is also called the degree of confidence c. the confidence level is often expressed as the probability or area 1 - α, where α is the complement of the confidence level d. the confidence level gives us the success rate of the procedure used to construct the confidence interval

a. there is a 1 - α chance, where α is the complement of the confidence level, that the true value of p will fall in the confidence interval produced from our sample

the test statistic of z = 1.32 is obtained when testing the claim that p > 0.5. complete parts (a) through (c) a. this is a _____ test b. p-value = c. make a conclusion

a. this is a right-tailed test b. p-value = 0.093 c. fail to reject H0. there is not sufficient evidence to support the claim that p > 0.5

the test statistic of z = 1.20 is obtained when testing the claim that p=/ 0.795. complete parts (a) through (c) a. this is a ____ test b. p-value = c. make a conclusion

a. this is a two-tailed test b. p-value = 0.230 c. fail to reject H0. there is not sufficient evidence to support the claim that p=/ 0.795

which concept below is not a main idea of estimating a population proportion? a. using a sample statistic to estimate the population proportion is utilizing descriptive statistics b. we can use a sample proportion to construct a confidence interval to estimate the true value of a population proportion c. the sample proportion is the best point estimate of the population proportion d. knowing the sample size necessary to estimate a population proportion is important.

a. using a sample statistic to estimate the population proportion is utilizing descriptive statistics

different hotels in a certain area are randomly selected, and their ratings and prices were obtained online. using technology, with x representing the ratings and y representing price, we find that the regression equation has a slope of 125 and a y-intercept of -374. complete parts (a) and (b) a. what is the equation of the regression line? b. what does the symbol y with ^ above it represent?

a. y with ^ above it = -374 + (125) x b. the symbol y with ^ above it represents the predicted value of price

claim: the mean pulse rate (in beats per minute) of adult males is equal to 69.1 bpm. for a random sample of 168 adult males, the mean pulse rate is 70.5 bpm and the standard deviation is 11.3 bpm. complete parts (a) and (b) a. express the original claim in symbolic form b. identify the null and alternative hypotheses

a. µ = 69.1 bpm b. H0: µ = 69.1 bpm; H1: µ =/ 69.1 bpm

which of the following is not a true statement about error in hypothesis testing? a. a type I error is making the mistake of rejecting the null hypothesis when it is actually true b. a type I error is making the mistake of rejecting the null hypothesis when it is actually false c. the symbol α represents the probability of a type I error d. a type II error is making the mistake of failing to reject the null hypothesis when it is actually false

b. a type I error is making the mistake of rejecting the null hypothesis when it is actually false

which of the following is not one of the three common errors involving correlation? a. the conclusion that correlation implies causality b. correlation does not imply causality c. mistaking no linear correlation with no correlation d. the use of data based on averages

b. correlation does not imply causality

which of the following is not a criterion for making a decision in a hypothesis test? a. if p-value <= α, the decision is to reject the null hypothesis. otherwise, we fail to reject the null hypothesis b. if the p-value is less than 0.05, the decision is to reject the null hypothesis. otherwise, we fail to reject the null hypothesis c. if a confidence interval does not include a claimed value of a population parameter, the decision is to reject the null hypothesis d. if the test statistic falls within the critical region, the decision is to reject the null hypothesis

b. if the p-value is less than 0.05, the decision is to reject the null hypothesis. otherwise, we fail to reject the null hypothesis

which of the following is not a requirement for a density curve? a. every point on the curve must have a vertical height that is 0 or greater b. the graph is centered around 0 c. the curve cannot fall below the horizontal axis d. the total area under the curve must equal 1

b. the graph is centered around 0

which of the following is not true about p-values in hypothesis test? a. the p-value is an area b. the p-value separates the critical region from the values that do not lead to rejection of the null hypothesis c. if the p is low, the null most go d. if the p is high, the null will fly

b. the p-value separates the critical region from the values that do not lead to rejection of the null hypothesis

which of the following calculations is not derived from the confidence interval? a. the point estimate of µ, x with a bar over it = (upper confidence limit) + (lower confidence limit) / 2 b. the population mean, µ = (upper confidence limit) + (lower confidence limit) c. difference between the limits, 2E = (upper confidence limit) - (lower confidence limit) d. the margin of error, E = (upper confidence limit) - (lower confidence limit) / 2

b. the population mean, µ = (upper confidence limit) + (lower confidence limit)

which of the following is not an advantage of pooling sample variances? a. hypothesis tests have more power b. we often know that σ1 = σ2 c. the number of degrees of freedom is a little higher d. confidence intervals are a little narrower

b. we often know that σ1 = σ2

which of the following would be information in a question asking you to find the area of a region under the standard normal curve as a solution? a. a probability is given b. a percentage is given c. a distance of the horizontal axis is given d. finding z subscript α

c. a distance of the horizontal axis is given

which of the following is not true? a. the area in any normal distribution bounded by some score x is the same as the area bounded by the equivalent z-score in the standard normal distribution b. a z-score is a conversion that standardizes any value from a normal distribution to a standard normal distribution c. a z-score is an area under the normal curve d. if values are converted to standard z-scores, then procedures for working with all normal distributions are the same as those for the standard normal distribution

c. a z-score is an area under the normal curve

which of the following is not equivalent to the other three? a. explanatory variable b. independent variable c. dependent variable d. predictor variable

c. dependent variable

which of the following is not needed to determine the minimum sample size required to estimate a population proportion? a. α b. z subscript α/2 c. standard deviation d. margin of error

c. standard deviation

which of the following is not a conclusion of the central limit theorem? a. the standard deviation of all sample means is the population standard deviation divided by the square root of the sample size b. the distribution of the sample means x will, as the sample size increases, approach a normal distribution c. the distribution of the sample data will approach a normal distribution as the sample size increases d. the mean of all sample means is the population mean µ

c. the distribution of the sample data will approach a normal distribution as the sample size increases

which of the following is not a property of the sampling distribution of the sample mean? a. the expected value of the sample mean is equal to the population mean b. the sample means target the value of the population mean c. the distribution of the sample mean tends to be skewed to the right or left d. the mean of the sample means is the population mean

c. the distribution of the sample mean tends to be skewed to the right or left

which of the following is not a descriptor of a normal distribution of a random variable? a. the graph of the distribution is bell-shaped b. the graph is centered around the mean c. the graph is centered around 0 d. the graph of the distribution is symmetric

c. the graph is centered around 0

which of the following does not describe the standard normal distribution? a. it is a normal distribution with a mean of 0 and a standard deviation of 1 b. the total area under the curve must equal 1 c. the graph is uniform d. the graph is symmetric

c. the graph is uniform

which of the following is not required to determine minimum sample size to estimate a population mean? a. the desired confidence level b. the desired margin of error c. the size of the population, N d. the value of the population standard deviation, σ

c. the size of the population, N

the ______ tells us that for a population with any distribution, the distribution of the sample means approaches a normal distribution as the sample size increases

central limit theorem

a(n) ______ equation expresses a linear relationship between a response variable y and two or more predictor variables

multiple regression

twenty different statistics students are randomly selected. for each of them, their body temperature (°​C) is measured and their head circumference (cm) is measured. if it is found that r = 0, does that indicate that there is no association between these two variables?

no, because while there is no linear correlation, there may be a relationship that is not linear

if we find that there is a linear correlation between the concentration of carbon dioxide in our atmosphere and the global temperature, does that indicate that changes in the concentration of carbon dioxide cause changes in the global temperature?

no. the presence of a linear correlation between two variables does not imply that one of the variable is the cause of the other variable

weights of golden retriever dogs are normally distributed. samples of weights of golden retriever dogs, each of size n = 15, are randomly collected and the sample means are found. is it correct to conclude that the sample means cannot be treated as being from a normal distribution because the sample size is too small?

no; the original population is normally distributed, so the sample means will be normally distributed for any sample size

the ______ hypothesis is a statement that the value of a population parameter is equal to some claimed value

null

in a scatter plot, a(n) _______ is a point lying far away from the other data points

outlier

express the confidence interval 0.555 <p < 0.999 in the form p^ +-E

p^ +-E = 0.777 +- 0.222

what are terms that can be used interchangeably with each other?

percentage, probability, and proportion

a ______ is a single value used to approximate a population parameter

point estimate

we say that there is a _____ correlation between x and y if the x-values increase as the corresponding y-values increase

positive

given a collection of paired sample data, the ______ y^ = b0 +b1x algebraically describes the relationship between the two variables, x and y

regression equation

the _____ is the best point estimate of the population mean

sample mean

what are the unbiased estimators of population parameters?

sample proportion used to estimate a population proportion, sample variance used to estimate a population variance, and sample mean used to estimate a population mean

when determining whether there is a correlation between two variables, one should use a _______ to explore the data visually

scatterplot

what's wrong with the following statement?: "because the digits 0, 1, 2, ..... , 9 are the normal results from lottery drawings, such randomly selected numbers have a normal distribution."

since the probability of each digit being selected is equal, lottery digits have a uniform distribution, not a normal distribution.

the ______ is a value used in making a decision about the null hypothesis and is found by converting the sample statistic to a score with the assumption that the null hypothesis is true

test statistic

find the area of the shaded region. the graph depicts the standard normal distribution with mean 0 and standard deviation 1. z= 0.95 and the graph is shaded to the left

the area of the shaded region is 0.8289

claim: most adults would erase all of their personal information online if they could. a software firm survey of 655 randomly selected adults showed that 99.4% of them would erase all of their personal information online if they could. make a subjective estimate to decide whether the results are significantly low or significantly high, then state a conclusion about the original claim

the results are significantly high, so there is sufficient evidence to support the claim that most adults would erase all of their personal information online if they could.

where would a value separating the top 15% from other values on the graph of a normal distribution be found?

the right side of the horizontal scale of the graph

determine whether the samples are independent or dependent: a data set includes the age at marriage for 160 randomly selected married couples

the samples are dependent because there is a natural pairing between the two samples

________ is the distribution of all values of the statistic when all possible samples of the same size n are taken from the same population

the sampling distribution of a statistic

assume that a randomly selected subject is given a bone density test. those test scores are normally distributed with a mean of 0 and a standard deviation of 1. draw a graph and find the probability of a bone density score between -1.66 and 1.66.

the sketch is bell-shaped with the area between -1.66 and 1.66 shaded to show that it is between -1.66 and 1.66

assume that a randomly selected subject is given a bone density test. those test scores are normally distributed with a mean of 0 and a standard deviation of 1. find the probability that a given score is less than 2.23 and draw a sketch of the region

the sketch is bell-shaped with the area to the left shaded at the 2.23 mark, to show that it is less than 2.23

assume that a randomly selected subject is given a bone density test. those test scores are normally distributed with a mean of 0 and a standard deviation of 1. draw a graph and find the probability of a bone density test score greater than -1.78.

the sketch is bell-shaped with the area to the right shaded at the -1.78 mark, to show that it is greater than -1.78

what is the difference between a standard normal distribution and a nonstandard normal distribution?

the standard normal distribution has a mean of 0 and a standard deviation of 1, while a nonstandard normal distribution has a different value for one or both of those parameters

a magazine provided results from a poll of 1000 adults who were asked to identify their favorite pie. among the 1000 respondents, 13% chose chocolate pie, and the margin of error was given as +-3 percentage points. describe what is meant by the statement that "the margin of error was given as +-3 percentage points"

the statement indicates that the interval 13% =-3% is likely to contain the true population percentage of people that prefer chocolate pie

a magazine provided results from a poll of 500 adults who were asked to identify their favorite pie. among the 500 respondents, 12% chose chocolate pie, and the margin of error was given as +-5 percentage points. what values do p^, q^, n, E, and p represent? if the confidence level is 95%, what is the value of α?

the value of p^ is the sample proportion the value of q^ is found from evaluating 1-p^ the value of n is the sample size the value of E is the margin of error the value is the population proportion α =

what is the relationship between the linear correlation coefficient r and the slope b1 of a regression line?

the value of r will always have the same sign as the value of b1

identify the type I error and the type II error that corresponds to the given hypothesis: the proportion of people who write with their left hand is equal to 0.26

type I error: reject the claim that the proportion of people who write with their left hand is 0.26 when the proportion is actually 0.26 type II error: fail to reject the claim that the proportion of people who write with their left hand is 0.26 when the proportion is actually different from 0.26

identify the type I error and the type II error that corresponds to the given hypothesis: the percentage of adults who have a job is equal to 88%

type I error: reject the null hypothesis that the percentage of adults who have a job is equal to 88% when that percentage is actually equal to 88% type II error: fail to reject the null hypothesis that the percentage of adults who have a job is equal to 88% when that percentage is actually different from 88%

A continuous random variable has a _____ distribution if its values are spread evenly over the range of possibilities

uniform

what is the correct interpretation of a 99% confidence interval such as 4.1 < µ < 5.6?

we are 99% confident that the interval from 4.1 to 5.6 actually does contain the true value of µ

a critical value, z subscript α, denotes the ______

z-score with an area of α to its right

the standard deviation of the distribution of sample means is _____

σ over the square root of n