Stat Final multiple choice

As the sample size decreases the mean of the sampling distribution will __________.

stay the same

Assume all members of the class were put into groups based on gender and a random sample of 10 students was selected from each group. identify the sampling method used

Stratified

When determining the sample size needed, if the amount of allowed error is decreased then the number of samples needed will ________ if all other elements are eld constant.

increase

All normally distributed datasets have a bell shaped curve with a given mean and standard deviation. The ________ of the distribution tells us how wide (or narrow) the curve is.

standard deviation

expresses the variability of the data

standard deviation (σ)

The standard error is also known as the _______.

standard deviation of the sampling distribution

What makes a probability distribution valid?

- all probabilities must be between 0 and 1 - the sum of all probabilities must equal 1

A park claims the probability of damaging your car is 0.20. Supposed 10 cars are selected at random (and the cars are independent of each other). What is the probability that a car is not damaged during the drive thru?

0.8 ( 1 - 0.2 = 0.8 )

What is the equation for a 90% confidence interval for the population mean (standard deviation known) will correctly calculate the margin of error?

1.645 [stnd dev / (sq root (n))]

What type of variable is the number of fans at a basketball game?

Discrete numerical

Which of the following 99% confidence intervals for the proportion of chicken breast that contain E. coli could we conclude that the proportion of chicken containing E. coli is less than 50%? a. (0.04, 0.44) b. (0.44, 0.90) c. (0.58, 0.64)

a. (0.04, 0.44)

If we know that 75% of the data falls above a give number which measure are we defining? a. First quartile b. interquartile range c. Second quartile d. Third Quartile

a. First Quartile

A park claims the probability of damaging your car is 0.20. Supposed 10 cars are selected at random (and the cars are independent of each other). If we are looking for the probability that at most two cars are damaged during the drive-thru which of the following is not a correct equation to find this probability? a. P (X = 2) + P (X = 1) b. P (X </= 2) c. P (X = 2) + P (X = 1) + P (X = 0) d. 1- P (X>2)

a. P (X = 2) + P (X = 1)

If you have a histogram that is left - skewed, how would you expect the mean and median to compare? a. mean < median b. mean = median c. mean > median d. can't be determined

a. mean < median

Ho : μ = 500 H1 : μ ≠ 500 Critical values = +/- 1.96 Test Statistic = 2.0 level of significance = 0.10 Assuming that the sample was randomly selected, the data was numerical, the population was normally distributed and the population standard deviation was not known for this problem, what test was performed? a. t test b. n test c. z test

a. t test

A survey was conducted to determine if students that attend USC are in favor of alcoholic beverages being sold at college athletic events. A random sample of 500 students was taken and it was determined that 80% of students samples are in favor. Identify the population of interest.

all students that attend USC

In order to use the central limit theorem the we know the population data is normally distributed, we must take a minimum sample size of _____.

any sample size will work because the population data is normally distributed, if not then 30

On a normal curve, where does z = 0 fall on the curve?

at the middle of the curve

Determine if the follow two events are mutually exclusive: owning a car and owning a boat. a. Mutually exclusive b. Not Mutually exclusive c. Cannot be determined

b. Not mutually exclusive with mutually exclusive events, either one event or the other can occur, not both

Ho : pi <= 0.5 H 1 : pi > 0.5 What type of test is being performed using this hypothesis test? a. one tailed test - left/lower tail b. one tailed test - right/upper tail c. two tailed test

b. one tailed test - right/upper tail

Ho : pi <= 0.5 H 1 : pi > 0.5 Decision = Reject Ho Based on the decision of the hypothesis test, with of the following 95% confidence intervals would we expect to get? a. (0.01, 0.56) b. (0.23, 0.35) d. (0.52, 0.78)

c. (0.52, 0.78)

With a level of significance of 0.10, which of the following p - values would lead you o the conclusion to Do Not Reject Ho. a. -.012 b. 0.012 c. 0.12

c. 0.12 because p > level of significance 0.12 > 0.10

Ho : pi <= 0.5 H 1 : pi > 0.5 Which of the following correctly identifies the claim we are testing using this hypothesis test? a. is there evidence that the true population proportion is different than 0.5 b. is there evidence that the true population proportion is less or equal to 0.5 c. is there evidence that the true population proportion is greater than 0.5

c. Is there evidence that the true population proportion is greater than 0.5

Ho : μ = 500 H1 : μ ≠ 500 Critical values = +/- 1.96 Test Statistic = 2.0 level of significance = 0.10 Using methods discussed from the critical approach (identifying the rejection regions) and the value of the test statistic what would the decision be for this hypothesis test: a. accept Ho. b. Do Not Reject Ho c. Reject Ho

c. reject Ho draw rejection regions

Given a dataset that contains the value 4.002 which of the following provides the correct stem unit and leaf unit for a stem-and-leaf plot? a. stem unit = 100 leaf unit = 0.1 b. stem unit = 1000 leaf unit = 0.001 c. stem unit = 1.000 leaf unit = 0.001

c. stem unit = 1.000 leaf unit = 0.001

The following is the 95% confidence interval for the difference in the cost of a Yeti 30 oz cup at retailer A and retailer B: (-0.85, -0.65). Note: μ Retailer A - μ Retailer B. Based on this confidence interval, which of the following statements is true: a. it is possible that there is no difference in the average price of the cup at retailer A and retailer B. b. the price of the cup is always higher, on average, at retailer A. c. the price of the cup is always higher, on average, at retailer B .

c. the price of the cup is always higher, on average, at retailer B.

What notation represents a parameter (not a statistic)? a. s b. s^2 c. μ d. x(bar)

c. μ

Standard deviation of the sampling distribution of sample proportions

called the standard error

What type of a variable is the type of car a person owns?

categorical nominal

order is not important

combination

Which of the following probabilities is NOT valid? a. 0.0000001 b. 0.01 c. 1.0 d. 1.1

d. 1.1 because it is above 1

A park claims the probability of damaging your car is 0.20. Supposed 10 cars are selected at random (and the cars are independent of each other). Let our random variable X = the number of cars damaged during the drive-thru. Which of the following could not be a value of X based on the information provided? a. 0 b. 8 c. 10 d. 11

d. 11 because 10 cars are selected

Which of the following z - scores would be considered an unusual value? a. -1.5 b. 0.01 c. 1.5 d. 5

d. 5 normal z - scores are between -3.0 and 3.0

Ho : pi <= 0.5 H 1 : pi > 0.5 Which of the following must have to have been true in order to know that we could use a z test to perform this hypothesis test? a. the sample must have been randomly selected b. the sample must have consisted of a variable that was categorical. c. the sampling distribution of the statistic must have followed a normal distribution. d. all of the above are ideal situations to use a z test for proportions.

d. all of the above are ideal situations to use a z test for proportions

A park claims the probability of damaging your car is 0.20. Supposed 10 cars are selected at random (and the cars are independent of each other). Which of the following is not one of the properties needed to justify that the is a binomial distribution? a. There is a fixed number of independent trials b. The probability of a car getting damaged during the drive-thru is constant c. There are only two possible outcomes for each trial d. all of the above are properties that must be true to show this problem is a binomial

d. all of the above are properties that must be true to show this problem is a binomial

Which of the following represents the probability of getting a type I error in a hypothesis test? a. p - value b. test statistic c. hypothesized value d. level of significance

d. level of significance

In order to use the Empirical Rule, what shape must the distribution of the data have? a. left - skewed b. Random c. Right - skewed d. Symmetric

d. symmetric

Ho : pi <= 0.5 H 1 : pi > 0.5 Decision: reject Ho Based on the decision what is the correct interpretation? a. there is insufficient evident that the true population proportion is less than or equal to 0.5 b. There is sufficient evidence that the true population proportion is less than or equal to 0.5 c. There is insufficient evidence that the true population proportion is greater than 0.5 d. There is sufficient evidence that the true population proportion is greater than 0.5

d. there is sufficient evidence that the true population proportion is greater than 0.5

The margin of error used in the calculation of a confidence interval will _______ as you decrease the confidence level from .99 to .95.

decrease

Are the two samples pulled in the below description dependent or independent samples? School board members believe that adding a teacher's aide to each kindergarten class will increase instruction time. Twenty-six kindergarten classes were randomly selected and the daily instruction time was recorded; then a teacher's aid was added to each class and the daily instruction time was recorded again.

depended (matching)

two events that do not have any common outcomes

disjoint events

Correlation ___________ imply causation

does not

What is another term for mean

expected value

a 90% confidence interval is guaranteed to contain the true population parameter it is estimating.

false

"A and B" outdoes in both A and B

intersection of two events

What does a probability of 0 indicate?

it is an impossible event

How is the standard deviation of a sampling distribution affected if you decrease the sample size from 10,000 to 100.

it will increase

probability of a type 1 error

level of significance

Which of the following measures of center is affected by outliers?

mean

A survey was conducted to determine if students that attend USC are in favor of alcoholic beverages being sold at college athletic events. A random sample of 500 students was taken and it was determined that 80% of students samples are in favor. Assume the students sampled were asked, "Do you think the university should contribute to the delinquency of a minor by selling alcohol at college sporting events?" Identify the type of survey error.

measurement error

The t distribution (when n is small) has ________ area in the tails than the normal distribution because we have to use the sample standard deviation as an estimate of the population standard deviation

more

In order to determine if the sampling distribution of the sample proportion is approximately normally distributed, we need what to be true?

n(pi) >/= 15 and n(1-pi) >/= 15

In hypothesis testing, which hypothesis is always assumed to be true?

null

The ________ tells us the probability of getting a test statistic equal to or more extreme than the sample result, given that the null hypothesis is true.

p - value

order is important

permutation

What graphs can be used for categorical variables?

pie chart, bar graphs

Confidence intervals are interval estimates that are centered at the _______.

point estimate

statistic calculated to estimate the unknown population parameter

point estimate

Hypothesis testing is used to test the validity of a claim about a __________.

population parameter

For categorical data we want to make inferences about the _________

population proportion

A survey was conducted to determine if students that attend USC are in favor of alcoholic beverages being sold at college athletic events. A random sample of 500 students was taken and it was determined that 80% of students samples are in favor. The measurement provided - 80% of students sampled are in favor - was calculated using the _________ therefore it is considered a __________.

sample; statistic

The ________ distribution tells us what the sample statistic looks like.

sampling

The central limit theorem is used to determine if the __________ is known to be normally distributed.

sampling distribution of the sample mean

Which critical value do you use when you are calculating a 90% confidence interval for the true population mean when the population standard deviation is unknown?

t score

The ________ provides information that the sample mean was two standard errors away from assumed to be true population mean value of 500.

test statistic

What is the middle value on a bell - shaped curve?

the mean

when the null was true, but you rejected it.

type I error

what does the mean/expected value tell you?

what we expect the average to come out to

Is the outcome of a single coin toss mutually exclusive?

yes, one side or the other lands face up - not both at the same time

how many standard deviations from the mean an observation will fall

z - score