statistics test 2 (6,8&9)

In the same scenario as 8.15, suppose you obtained a mean of $167 spent on transportation and a standard deviation of $40. Calculate a 95% confidence interval for the mean and select the values that come closest to those that would fill the spaces in the following interpretation: we can be 95% confident that they mean amount of money spent on transportation lies between _____ and _____ .

$148 and $186

Click on the row and column headings for the table entry of .9474.

.02

Click on the row and column headings for the table entry that is closest to .8500.

.04

Click on the row and column headings for the table entry of .9699.

.08

Find the proportion of a numal curve by looking in the blue left side first than the top right side

.96 =z score of .8315

What proportion of scores falls below x = 25 in a normal distribution where = 65 and = 12? Round your answer to four decimal places.

0.0004

What is the z-score for a male whose height is 63.46 inches?

-2.14667

The student union wants to negotiate a subsidized bus pass with your school's administration. They have polled 270 students as to whether they support this proposal, which would add a small fee to their tuition since both the college and the students would share the cost. The union found that opinions were evenly split: 50% of students were in favor of the proposal, and the rest were opposed. The margin of error for their finding at the 90% level of confidence is ± _____ %.

0.05(0.0596)

Referring to Example 2 in the section above, suppose that a smaller sample size was used to conduct Nielsen ratings. What would the margin of error be (assume it is a ± value, in %) for a 95% confidence interval with a sample size of just 200 cases?

0.0694

Calculate Cohen's d for an experiment in which the mean and SD for the two groups being compared were as follows:Group 1: x̅ = 56, s = 18Group 2: x̅ = 50, s = 14

0.372104

Sort the following intervals in order of width, from narrowest to widest (assuming the SD is constant in all three cases).

1. 95% ci where n=500 2: 95% ci where n=100 3. 99% ci where n=100 ch 8

Sort these items into the order that you would use them in order to calculate the confidence interval for the mean.

1. Select a sample stat 2. select a desired confidence level 3. determine the margin of error using the standard error of the mean 4.specify the upper and lower limits of the confidence interval

Sort these items into the correct order according to the scientific method.

1. ask ques 2. background research 3. construct hypo 4. test hypo 5. anaylyze the data and draw conclusions 6. communicate results

For a population of IQ scores with µ = 100 and σ = 16, rank the following sample sizes from greatest to least in terms of the resulting σ_{x̄}.

1. n=10 2. n=15 3. n=18 4. n=25

Arrange the hypothesis testing steps in their correct order.

1. state null +alt hypo 2. determine alpha level 3. determine approp stat test 4.indentify the critical values of the test stat 6. calculate the test stat

Suppose that you are hired to conduct a survey of job satisfaction for a company with 500 employees across the country. One of the topics that you want to explore is telecommuting and you want to know how many miles that the employees have to travel in order to get to the office each day. Your sample of 200 of the employees showed that they travelled an average return journey of 10.5 miles daily, with a standard deviation of 6.0 miles. The margin of error for your finding at the 99% confidence level is ± _____ miles.

1.09?

Suppose that we have collected information on how much a sample of households spend on clothing per year. If we are 90% confident that the true population mean will lie between $1,500 and $2,100, the chance that the population mean will either be less than $1,500 or above $2,100 is _____ %.

10%

For a population of IQ scores with µ = 100 and = 16, match the sample sizes with the value of σ_\bar{x} that will result according to the central limit theorem.

10->5.06 16-> 4 22->3.41 35-> 2.7

The mean of a population of IQ scores is 100. What is the mean of the distribution of sample means for samples of size 64?

100?

One of the relatively uncommon instances in which researchers know the population standard deviation is in the case of the Intelligence Quotient or IQ test. In general, the average IQ score in large, diverse populations is 100 and the standard deviation is 15. Suppose that your sample of 300 members of your community gives you a mean IQ score of 108. Calculate a 90% confidence interval for the mean and indicate which answer set comes closest to those that would fill the blanks in the following interpretation: we can be 90% confident that the mean IQ score in this community lies between _____ and _____ .

106.46 and 109.54

A normal curve portraying the weights of machine-filled potato chip bags is centered around 16 ounces, which is the manufacturer's target weight. Any other weight is an error in production. Knowing what we know about a bell curve, which of the weights below will occur more frequently than the others?

15

What is the raw score that corresponds to a z-score of -0.18 when = 168 and = 25?

163.5? ch 6

Suppose that you are a city planner who obtains and sample of 20 randomly selected members of a mid-sized town in order to determine the average amount of money that residents spend on transportation each month (such as fuel, vehicle repairs, and public transit). To 3 decimal places, what is the critical value for the 95% confidence interval?

2.093

Which of the following are not possible means from the following population ​[12, 14, 18, 18, 20] when the sample size is 2?

25?

What is the z-score for a male whose height is 78.06 inches?

3?

99% interval

4 standard deviations

In a normally distributed population, what percentage of scores fall below the mode?

50%

What is the raw score that corresponds to a z-score of -1.15 when = 75 and = 15?

57.75

Which possible sample mean listed below will be larger than most other possible sample means for the data above?

65 78 or 88

Sort the following four samples in terms of the size of their margin of error, from smallest to largest.

90% -n500 95%n=500 90%n=200 95%n=200

The highest level of confidence that is conventionally used with large samples is %.

99

Which of the following would be an example of a point estimate?

?The percentage of Gallup poll respondents who said that they intended to vote in the next U.S. presidential election. B The mean age of a sample of registered voters from the most recent U.S. presidential election. & he average temperature of newborn infants is within three degrees of 96.8º F.

Which of the following do we not need to know to find a raw score when using a probability from the Standard Normal Table?

n. we need mue, theta, and z.?

Suzanne needs to find the probability that the mean verbal IQ of a sample of 45 students at her school will be 110 or greater. Which formula should she use?

z=x-muexbar/theta xbar

Given a research hypothesis that the average test score of students in online class sections will be different than the average test score of students in classroom-based sections, identify the correct null hypothesis:

H0: µ1 = µ2

Given the statement, H1: µ1 > µ2, what is the correct null hypothesis?

H0: µ1 ≤ µ2

What is the difference between an experimental and non-experimental study?

In an experiment study the IV is actively manipulated while in a non-experimental study the IV is not actively manipulated

What is the function of the comparison distribution?

It provides the statistical distribution to which the results of a study are to be compared.

While the main advantage of a point estimate is its _____, its main disadvantage is its _____.

Precision; inaccuracy

Imagine that you were studying the weight of children in the United Kingdom. Which of the following would be an example (or examples) of an interval estimate?

The average weight of all British 5-year-olds is between 39.5 and 44.5 pounds. B The proportion of children who are overweight is estimated to be between 35% to 45%.

Which of the following defines a Type I error?

The probability of rejecting the null hypothesis when it is true

Which of the following symbols is used to represent the mean of the distribution of sample means?

μ_\bar{x}

Confusing Which one of the following sampling methods is more likely to be appropriate for calculating confidence intervals?

Use the telephone book to gather all of the phone numbers of 300 members of a small town and draw 150 of them out of a large hat

A two-tailed test is appropriate for a hypothesis that does not predict a outcome.

more than or less than

Which of the following are key components of an experiment?

a null hypothesis and an alternative hyp a statement defining how the results are to be measured/interpreted identification of the population of interest Descriptions of the variable being tested

A distribution of sample means gives us possible sample means, and the frequency with which they occur.

all or finite

As our confidence level increases, the width of our confidence interval ______.

also increases

A 95% level of confidence means that 95 of every 100 samples taken would do which of the following?

capture the sample mean in another sample? capture the mean from the population

The null hypothesis is stated so as to be _________ to the alternative hypothesis.

complementary

Referring to the data in Example 1 in the section above, what if we wanted to increase our level of confidence in the Angela May election poll to 99%? Match the following components of the C.I. with their correct values.

critical value:2.58 Statistic:.55 margin of error =-9% upper limit:46% lower limit:64% standard error for prop: 0.035

The appropriate comparison distribution for comparing an individual score to a known population parameter is a distribution of sample means.

false

The purpose of hypothesis testing is to establish the truth of the research hypothesis.

false?

other things being equal, which of the following will increase the power of a hypothesis test?

increasing sample size

A complete, testable hypothesis includes several defining elements, including which of the following.

it explicitly identifies the groups being compared

The reason that you would select the option that you did above is due to what is known as _____.

law of large numebrs

A research hypothesis that makes a prediction of a lower score on a measure of the DV would require a ________.

left-tailed test

Another name for sampling error is _____ error.

margin of ?

Imagine that you are conducting a poll to determine the percentage of adults who gamble at least once a month. As your sample size increases (let us say from 100 to 400 cases), which of the following becomes true?

margin of error becomes smaller

sqrt of p hat * q hat/n

margin of error?

The appropriate comparison distribution to use when comparing a sample mean to a known population mean is a distribution of ______.

means

Suppose that you run a survey research firm and have a reasonably good budget but you want to impress your client with your cost efficiency as well as data quality. You can select from three possible options. Which option would you select?

n=1,500 and margin of error +/- 1.1

The null hypothesis is considered as the ______ outcome.

no effect

An effect size of zero would indicate __________.

no effect of the dv

Most real-world research hypotheses are _________ in nature.

non directional?

A researcher is planning a study and is considering various options for alpha. Selecting a larger alpha value will result in decreased

non-rejection region

With repeated samples of M&M candies, eventually the sampling distribution will become approximately _____.

normal

In an experimental situation, support is said to accrue to the alternative hypothesis under what condition(s)?

null is rejected

Level of confidence refers to the probability that our interval estimate will contain the _____.

population parameter

Along with whether a result has statistical significance, a researcher should also be concerned with whether the result has significance.

practical

The core logic of hypothesis testing is built around the concept of _______.

proof by contradiction

constructing a testable hypothesis is one step in the

scientific method

One of the two key assumptions for confidence intervals is that the researcher has used _____ . (Hint: 3 words)

simple random sampling

Which of the following determines alpha?

size of rejection region

With a two-tailed test, the rejection region is __________.

split between the two tails of the distribution

Cohen's d is used to calculate a __effect size.

standardarized measure of

Which areas of a normal distribution can be found using subtraction after a value from the Standard Normal Table has been found?

the are to the right of a z score and the area between the mean and the z score

Where in a normal curve can most observations be found?

the center

What is the size of the margin of error due to?

the size of the sample (n)

the lowest 15% of the distribution are

the two lowest sections on a bell curve

The P-value of an outcome is the probability of obtaining a result at least as extreme as the one observed if the null hypothesis is _________.

true

Match each discrete variable with the appropriate continuity correction to use with the normal distribution.

x> 25=x>25.5 x> or equal to 25= x>or equal to 24.5 x<25, x<24.5 x< or equal to 25, x< or equal to 25.5 (ch 6 #30)

In a binomial distribution, p = .15 and n = 50. Can the normal approximation to the binomial distribution be used?

yes?

In a binomial distribution, p = .70 and n = 25. Can the normal approximation to the binomial distribution be used?

yes?