# Quiz 8: Hypothesis Testing Using the One-Sample T-Test

Psychology

Q 1Q 1

When is a t-test used instead of a z-test?
A)When the population μ is known
B)When the population deals with two samples
C)When the population standard deviation is known
D)When the population standard deviation is unknown

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D

Q 2Q 2

What is ?
A)The estimated population standard deviation
B)The population standard deviation
C)The estimated standard error of the mean
D)The standard error of the mean

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C

Q 3Q 3

Which of the following is one of the requirements of a one-sample t-test?
A)The obtained scores are either ordinal or interval.
B)The population standard deviation is estimated by computing .
C)The population standard deviation is known.
D)The population distribution is skewed.

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B

Q 4Q 4

What does the value indicate?
A)The probability of rejecting the null hypothesis
B)The probability of retaining the null hypothesis
C)How far the population mean, μ, is from the mean of the sampling distribution of means
D)How far the sample mean is from the μ of the sampling distribution of means

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Multiple Choice

Q 5Q 5

Which of the following requirements is common to both the z-test and the one-sample t-test?
A)Alpha is selected to be 0.01.
B)The raw score population forms a normal distribution, and the population mean and standard deviation are known.
C)The standard deviation of the raw score population is estimated by .
D)There is one random sample of interval or ratio scores.

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Q 6Q 6

Colin has computed the variance for his 10 raw scores and obtained = 16.37.He then computed as follows: What is wrong?
A)Colin first took the square root of and put this into the formula for .He should have used the = 16.37 value.
B)Colin should have divided here by N - 1.
C)Colin should not have taken the square root of 4.046/10 because he needs in the formula for the t-test.
D)There is nothing wrong with the way Colin has done this problem.

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Q 7Q 7

Which of the following is not one of the steps in a one-sample t-test?
A)Create the null hypothesis H

_{0}) and alternative hypothesis H_{a}). B)Create the sampling t-distribution and find in the t-tables. C)Compute . D)Compare to .Free

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Q 8Q 8

How is the t-distribution defined?
A)The distribution of all possible values of t
B)How far the sample mean is from the μ of the sampling distribution in estimated standard error units
C)The distribution of all possible values of t for random samples having the same N from the population described by
D)The distribution of all possible values of t for random samples having the same N from the population described by

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Multiple Choice

Q 9Q 9

For a given level of α, when does ?
A)When the degrees of freedom for the t-test equal the degrees of freedom for the z-test
B)When the degrees of freedom for the t-test equal N for the z-test
C)When the degrees of freedom for the t-test are greater than 120
D)There is never a situation when

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Multiple Choice

Q 10Q 10

For a two-tailed test with α = 0.05, the value is
A)either +1.96 or -1.96.
B)both +1.96 and -1.96.
C)either +1.645 or -1.645.
D)different for each df.

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Q 11Q 11

Unless we use the correct from the t-distribution for the appropriate N,
A)we will fail to reject .
B)we will always reject .
C)the probability of making a Type I error will increase.
D)the probability of making a Type I error will not equal α.

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Q 12Q 12

What happens to the absolute value of as df increases? It
A)decreases.
B)increases.
C)remains the same.
D)increases or decreases depending on whether is positive or negative.

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Multiple Choice

Q 13Q 13

Which of the following would make it more likely your t-test will be significant?
A)Decreasing the degrees of freedom
B)Using a one-tailed test rather than a two-tailed test
C)Changing α from 0.05 to 0.01
D)Computing a confidence interval for μ

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Q 14Q 14

After determining your one-tailed t-test is significant, what should you do?
A)See if the test is still significant at a lower α.
B)See if the test is still significant at a higher α.
C)See if the test is still significant if you use a two-tailed test.
D)Compute a confidence interval for μ.

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Multiple Choice

Q 15Q 15

The precise location on the dependent measure where we expect our population mean to fall refers to
A)point estimation.
B)interval estimation.
C)margin of error.
D)confidence interval.

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Q 16Q 16

Interval estimation suggests a where we expect the to fall.
A)range of values; population parameter
B)specific value; population parameter
C)range of values; sample mean
D)specific value; sample mean

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Q 17Q 17

Suppose a poll has been conducted on Americans' favorable attitudes towards a certain issue.If it is reported that Americans are 56%+4% in favor of the issue, which of the following is not a possible value represented within the margin of error?
A)51%
B)53%
C)56%
D)60%

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Q 18Q 18

When is a sample mean likely to represent a particular population mean?
A)It depends on sampling error.
B)It depends on our alpha.
C)When our t-obtained is greater than the expected value of t.
D)When we reject the null hypothesis.

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Q 19Q 19

To achieve statistical significance for a one-sample t-test,
A)the t-obtained must be larger than the t-critical.
B)the t-obtained must equal the t-critical.
C)the t-obtained must be less than the t-critical.
D)the t-obtained must differ from the t-critical by .05.

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Q 20Q 20

Suppose we have a 95% confidence interval of 12.23 and 16.75.What does this mean?
A)We are 95% confident that the true population mean is between 12.23 and 16.75.
B)We are 95% confident that the true population mean is either 12.23 or 16.75.
C)The average of 12.23 and 16.75 is probably the true population mean.
D)We are at least 95% certain that neither a Type I nor a Type II error was made.

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Q 23Q 23

If a researcher reports a one-sample t-test with df = 24, how many individuals participated in this study?

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Q 24Q 24

Using the data given below, perform a two-tailed t-test to compare the sample mean to μ = 35.5.Use α = .05

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Q 26Q 26

Some people claim psychology is common sense.If this is true, then students who have not taken psychology courses should be able to predict the outcomes of experiments as well as psychology majors.If it is not, nonpsychology students should perform worse than psychology students.Psychology students typically predict outcomes with μ = 69% accuracy.A sample of 15 nonpsychology students predicted with = 60% accuracy.The = 2.606.If appropriate, calculate the 95% confidence interval for nonpsychology students.

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Q 27Q 27

Suppose you conduct an experiment with 20 subjects and the turns out to be 0.69, which is not statistically significant.What is the correct way to report your results?

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Q 28Q 28

Using the following data, compute the t-statistic.Use a known population mean of 28, a two-tailed test, and = 0.05.
22 19 23 26 18 22 21
31 30 25 20 24 25 23

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Q 29Q 29

Using the following data, compute the t-statistic.Use a known population mean of 20, a one-tailed test in the upper tail, and = 0.05..
22 19 23 26 18 22 21
31 30 25 20 24 25 23

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Q 30Q 30

Using the following data, conduct a one-tailed t-test in the upper tail.Use a known population mean of 49 and α =
.05.
51 48 52 50 48 52 50 48 52 54
50 52 54 47 49 53 47 46 50 51

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Q 31Q 31

Using the following data, conduct a two-tailed t-test.Use a known population mean of 49 and α = .05.
51 48 52 50 48 52 50 48 52 54
50 52 54 47 49 53 47 46 50 51

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Q 32Q 32

Using the following data, conduct a two-tailed t-test.Use a known population mean of 49 and α = .01.
51 48 52 50 48 52 50 48 52 54
50 52 54 47 49 53 47 46 50 51

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Q 33Q 33

Using the following data, calculate the sample mean.
55 48 59 50 48 52 50 48 57 54
50 52 54 43 44 53 40 46 50 51

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Q 34Q 34

Using the following data, calculate the sample standard deviation.
55 48 59 50 48 52 50 48 57 54
50 52 54 43 44 53 40 46 50 51

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Q 35Q 35

Using the following data, calculate the standard error of the mean.
55 48 59 50 48 52 50 48 57 54
50 52 54 43 44 53 40 46 50 51

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Q 36Q 36

Using the following data, conduct a two-tailed t-test.Use a known population mean of 49 and α = .05.
55 48 59 50 48 52 50 48 57 54
50 52 54 43 44 53 40 46 50 51

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Q 37Q 37

Using the following data, conduct a one-tailed t-test in the upper tail.Use a known population mean of 49 and α =
.05.
55 48 59 50 48 52 50 48 57 54
50 52 54 43 44 53 40 46 50 51

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Q 38Q 38

Suppose you conduct a one-tailed t-test and your results are significant at both the .05 and .01 levels.What should you report and why?

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Q 40Q 40

Suppose we have a sample mean of 12, estimate standard error of the mean of 2.5, and a t-critical value of 2.306.What would be the lower and upper limits of our confidence interval?

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Q 41Q 41

Suppose you've read about a poll conducted by a certain media outlet surveying the popularity of the U.S.President.This poll puts the President's approval rating at 49.7% +3.5%.Would would be the range that we would expect the actual population values to fall?

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Q 42Q 42

Suppose you're computing a one-sample t-test and you just finished computing your t-obtained.What is the next step for you to take?

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Q 43Q 43

What is the name of the procedure we can use in the unlikely event that our t-obtained value falls between two t- critical values in the t-table?

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