AP Stats two-sample t test conditions practice questions

This study set contains practice questions for AP Statistics focusing on the conditions necessary for conducting two-sample t tests. Perfect for preparing for the AP exam with real-world examples.

Ethan2010·28 flashcards·28 questions
APmathematicsstatistics
0
Known
1 / 28
0
Learning
Front

What assumption is required for normality?

Tap to flip
Back

Both sample distributions should be approximately normally distributed, especially if sample sizes are small.

Tap to flip
Got it
Still learning

Quiz(28 questions)

Question 1 of 28

1. What assumption must be checked regarding the distributions of the samples when conducting a two-sample t-test?

Terms in this Study Set(28)

Two-Sample t-Test Conditions(16)

What assumption is required for normality?

Both sample distributions should be approximately normally distributed, especially if sample sizes are small.

True or False: Sample sizes must be equal for a two-sample t-test.

False. Sample sizes can vary, but both should be sufficiently large or normal.

Fill in the blank: The two-sample t-test assumes that the two samples are __________.

independent from each other.

What condition must be met regarding variance?

The variances of the two populations should be approximately equal (homogeneity of variance).

When is a two-sample t-test appropriate?

When comparing means from two independent groups, like test scores of students from two different schools.

Example scenario: Is a two-sample t-test valid?

Comparing earnings of male and female employees in a company. - Independent samples - Sufficient sample size - Normal distributions.

True or False: Outliers can significantly affect t-test results.

True. Outliers can skew results and violate normality assumptions.

What is the implication of unequal variances?

Use Welch's t-test, which adjusts for unequal variances in the two samples.

Cause → Effect: What happens if samples are not independent?

The results of the t-test become invalid, leading to incorrect conclusions.

Define 'independent samples.'

Samples where the selection of one does not influence the selection of the other.

When can we use the t-test for large samples?

If sample sizes are greater than 30, normality assumptions are less critical due to the Central Limit Theorem.

Example: Compare two brands of milk.

Brands A and B are tested for fat content. - Independent samples - Normal distribution assumed for each.

What is 'homogeneity of variance'?

The condition where the variances of the two populations being compared are equal or similar.

True or False: Non-normal data can be used if sample sizes are small.

False. Non-normal data with small samples violates assumptions of the t-test.

What to check before performing a t-test?

1. Normality of data 2. Independence of samples 3. Equality of variances.

Fill in the blank: The t-test can compare __________ between two groups.

mean values of a quantitative variable.

Application of Two-Sample t-Test(12)

Scenario: Two gyms compare average weights.

Gym A: 150 lbs, Gym B: 160 lbs. Use a two-sample t-test to determine if the difference is significant.

When to use a two-sample t-test?

When comparing means from two independent groups, e.g., test scores from two different schools.

True or False: Two-sample t-tests require equal sample sizes.

False. They can handle unequal sample sizes.

Fill in the blank: A two-sample t-test can help assess differences in ____ between groups.

means.

Interpretation question: A p-value of 0.03 was found.

There is significant evidence to reject the null hypothesis at the 0.05 level.

Comparing means of men vs. women salaries.

Men: 60,000,Women:\displaystyle 60,000, Women: 55,000. T-test results indicate a significant difference.

Scenario: Testing two teaching methods' effectiveness.

Method A: 85% pass rate, Method B: 78%. Conduct a two-sample t-test to compare effectiveness.

True or False: Two-sample t-tests assume normal distribution.

True. Both groups must be normally distributed, especially with small samples.

What does a confidence interval tell us?

The range in which the true difference between group means likely falls.

Example: Average monthly rent comparison.

Apartment A: 1,800,ApartmentB:\displaystyle 1,800, Apartment B: 2,000. Analyze with two-sample t-test for significance.

Define: Independent samples.

Samples collected from different populations, e.g., students from two different colleges.

Cause and effect: Larger sample sizes lead to ____ in t-test results.

more reliable estimates.

Questions in this Study Set(28)

1. What assumption must be checked regarding the distributions of the samples when conducting a two-sample t-test?

A.Both samples should be approximately normally distributed.
B.Both samples must have equal sizes.
C.Both samples must have the same median.
D.Both samples must be dependent.

2. What is the primary assumption of the two-sample t-test regarding the populations being compared?

A.The populations must have equal variances.
B.The samples should be of equal size.
C.The populations must be normally distributed.
D.The samples must be dependent.

3. True or False: The two samples in a two-sample t-test must be from the same population.

A.True
B.False
C.Only if the samples are large.
D.Only if comparing means.

4. In a study comparing test scores from two different classes, Class A has an average score of 76 and Class B has an average score of 82. Which scenario requires a two-sample t-test?

A.Comparing Class A's scores to Class A's previous year's scores.
B.Comparing scores of Class A to Class B.
C.Comparing Class B's scores to the national average.
D.Comparing Class A's scores to Class C's scores from the same year.

5. Fill in the blank: A two-sample t-test assumes that the samples have __________ variances.

A.equal
B.no
C.varying
D.unknown

6. True or False: A two-sample t-test can only be used when both groups have a sample size greater than 30.

A.True
B.False
C.Only if variances are equal.
D.Only for normally distributed data.

7. In which scenario is a two-sample t-test most appropriate?

A.Comparing the average test scores of students from two different schools.
B.Comparing the same group's scores over two years.
C.Comparing a single group's scores to a fixed value.
D.Comparing the total number of students in two classes.

8. Fill in the blank: The two-sample t-test can help determine if there is a statistically significant difference in the ____ of two groups.

A.variances
B.medians
C.means
D.sample sizes

9. Is the following scenario valid for a two-sample t-test? Comparing the average salaries of engineers and scientists at a company.

A.Yes, both groups are independent.
B.No, the samples are not large enough.
C.Yes, but only if variances are equal.
D.No, engineers and scientists are dependent.

10. A researcher wants to analyze the average daily spending of two grocery stores. Store A reports an average of 85,andStoreBreports\displaystyle 85, and Store B reports 90. If the t-test shows a p-value of 0.04, what does this indicate?

A.There is no significant difference in spending.
B.There is significant evidence to reject the null hypothesis.
C.The average spending is the same.
D.The samples are not independent.

11. True or False: Outliers can impact the results of a two-sample t-test.

A.True
B.False
C.Only if the samples are small.
D.Only in the presence of equal variances.

12. When applying a two-sample t-test to analyze the difference in the average time taken to commute to work for two groups, which of the following is NOT a necessary condition?

A.Independence of samples
B.Normality of the distribution
C.Equal variances
D.Random sampling

13. What should be done if the variances of the two samples are significantly different?

A.Use Welch's t-test.
B.Increase the sample size.
C.Combine the samples.
D.Ignore the variance difference.

14. If a two-sample t-test results in a confidence interval of (1.5, 4.5), what does this imply about the difference between group means?

A.The means are equal.
B.The difference between means is not significant.
C.The true difference is likely between 1.5 and 4.5.
D.The sample sizes are too small.

15. Cause → Effect: What happens if the samples in a two-sample t-test are dependent?

A.The t-test results become invalid.
B.The t-test will still work as expected.
C.The sample size needs to be doubled.
D.The means will always be equal.

16. In a comparison of the average salaries of two different job positions, Position A earns 75,000andPositionBearns\displaystyle 75,000 and Position B earns 80,000 with a t-test resulting in a p-value of 0.10. What can we conclude?

A.There is a significant difference in salaries.
B.We fail to reject the null hypothesis.
C.Both positions have the same average salary.
D.The sample sizes are inadequate.

17. What is the definition of 'independent samples' in the context of a two-sample t-test?

A.Samples that do not affect each other's selection.
B.Samples that come from the same population.
C.Samples that are equal in size.
D.Samples that have the same mean.

18. Which of the following scenarios is best suited for a two-sample t-test?

A.Measuring the weights of a single group before and after a diet.
B.Comparing the heights of plants in two different fertilizers.
C.Analyzing the test scores of students from the same class.
D.Assessing the reaction times of participants before and after a training session.

19. When can you use the t-test for large samples?

A.If the sample sizes are greater than 30.
B.If the samples are normally distributed.
C.If the variances are equal.
D.If the samples are dependent.

20. If a researcher obtains a larger sample size for one of the groups in a two-sample t-test, what effect does this have on the test results?

A.It reduces the standard deviation.
B.It makes the t-test invalid.
C.It increases the power of the test.
D.It guarantees a significant difference.

21. Consider two brands of yogurt compared for sugar content. This test is valid if:

A.Both brands are independent and normally distributed.
B.Both brands have the same sugar content.
C.The brands are dependent.
D.The sample sizes of brands are equal.

22. In an analysis comparing average daily sales of two different stores, Store X has an average of 500andStoreYhasanaverageof\displaystyle 500 and Store Y has an average of 550 with a t-test showing a statistically significant result. What does this tell us?

A.Sales of Store Y are equal to Store X.
B.Store X has higher sales than Store Y.
C.There is likely a significant difference in sales.
D.The sales data cannot be compared.

23. What does 'homogeneity of variance' refer to?

A.The variances of the two populations being equal.
B.The means of the two populations being equal.
C.The sample sizes being equal.
D.The samples being dependent.

24. Which of the following scenarios would NOT be appropriate for conducting a two-sample t-test?

A.Comparing average heights of students from two different schools.
B.Evaluating the effectiveness of two different diets on the same group of individuals.
C.Analyzing the average income of two different cities.
D.Comparing test scores from two separate classes of students.

25. True or False: Non-normal data can still be used for a two-sample t-test if the sample sizes are large.

A.True
B.False
C.Only if the variances are equal.
D.Only if the data is paired.

26. What are the key conditions to check before performing a two-sample t-test?

A.Normality, independence, and equality of variances.
B.Sample sizes must be equal.
C.All samples must be paired.
D.Data must be categorical.

27. Fill in the blank: The t-test can compare __________ between two groups.

A.mean values of a quantitative variable.
B.totals of categorical variables.
C.the number of observations.
D.the proportions of a population.

28. Which of the following is NOT a condition that must be satisfied before conducting a two-sample t-test?

A.Both samples must be independent
B.Both samples must come from normally distributed populations
C.Both samples must have equal sample sizes
D.The variances of the two populations should be similar

Related Study Sets

Create Your Own Study Set

Upload a PDF, paste your notes, or describe a topic – AI generates flashcards, quizzes and more in seconds.