TRUE OR FALSE 1. A t-test is used when the population standard deviation is known. 2....

TRUE OR FALSE

1. A t-test is used when the population standard deviation is known.

2. The degrees of freedom in a t-test is one less than the margin of error.

3. A confidence interval can only be found when the standard deviation of the population is known.

4. The margin of error for a t-test is calculated using the sample mean.

5. The null hypothesis is a claim made about the sample.

6. The significance level is denoted by n.

7. If the conclusion of a hypothesis test is “fail to reject the null hypothesis,” then the results are statistically significant.

8. A 95% confidence interval for a population mean must be calculated using the sample mean.

9. A z-score is a test statistic.

10. A t-statistic is the same for a 95% confidence interval and a 90% confidence interval regardless to the same size.

Expert Solution

milcah answered 5 months ago

1. A t-test should be used when the standard deviation of the population is known, whereas...

1. A t-test should be used when the standard deviation of the population is known, whereas a z-test should be used when the standard deviation of the population is unknown. True or False? 2. If r = 0.72, what proportion of the variance in Y is accounted for by it's relationship with X? A. .72 b. .52 c. .36 d. .85 3.Jane conducts a Pearson correlation to assess the relationship between years of marriage and happiness from data collected from...

A certain IQ test is known to have a population mean of 100 and standard deviation...

A certain IQ test is known to have a population mean of 100 and standard deviation of 15 in the general population. You want to test whether psychology majors have a different average IQ than the population as a whole. Assume the variance of IQ is the same for Psych majors as it is in the general population. Suppose that Psychology majors actually have an average IQ of 108. If you do a 2-tailed test at α= .05 with a...

TRUE OR FALSE QUESTIONS: 1. we usually do not know the population standard deviation (σ) so...

TRUE OR FALSE QUESTIONS: 1. we usually do not know the population standard deviation (σ) so estimate it using the sample standard deviation (s). 2. The t distribution adjusts for increased sampling variability in small samples, it is more appropriate than the z distribution and we use the sample standard deviations (s) to estimate the population standard deviations (σ). 3. If we cant assume that the population standard deviations are equal in both groups (i.e., σ1 ≠ σ2), then we...

1. From a population of 540 that is known to have a standard deviation of 1,368,...

1. From a population of 540 that is known to have a standard deviation of 1,368, a sample of 60 individuals. The mean of this sample is found to be 6.2. a) Find the standard error of the mean. b) Construct an interval estimate around the sample mean, using the standard error of the mean calculated for 96% of cases. 2. A test of car safety in the State of Carolina found that the tire pressure for a sample of...

1) The population standard deviation for waiting times to be seated at a restaurant is known...

1) The population standard deviation for waiting times to be seated at a restaurant is known to be 10 minutes. An expensive restaurant claims that the average waiting time for dinner is approximately 1 hour, but we suspect that this claim is inflated to make the restaurant appear more exclusive and successful. A random sample of 30 customers yielded a sample average waiting time of 50 minutes. Is there evidence to say that the restaurant’s claim is too high? Insert...

Item Sample Mean 1 Population standard deviation of 1 n1 Sample Mean 2 Population Standard Deviation...

Item Sample Mean 1 Population standard deviation of 1 n1 Sample Mean 2 Population Standard Deviation 2 n2 7 18 6 169 12 12 121 0.01 Perform a Two-tailed hypothesis test for two population means.

Is the z-test the same as the t-test but only used when we know the true...

Is the z-test the same as the t-test but only used when we know the true value of population mean's variance? But in practice, I'm assuming that the population mean's variance is never observed so I'm confused why we use the z-test. When will the z-test be helpful when the t-test is not if we never know the population mean's variance in real life? What are the other two differences between the two tests?

1)True or False: Ambiguity is a type of vagueness True False 2)True or False: When determining...

1)True or False: Ambiguity is a type of vagueness True False 2)True or False: When determining whether a report of an argument should be treated as an argument, it is important to consider the context in which the report is made. True True False 3) True or False: In a V argument with two premises, if one of the premises is false, then the argument is definitely weak True False 4) True or False: A report of an argument can...

A confidence interval for the population mean when the population follows the normal distribution and the population standard deviation is known is computed by? Provide examples.

Question 3 A confidence interval for the population mean when the population follows the normal distribution and the population standard deviation is known is computed by? Provide examples. Question 6 What are the factors that determine the sample size? How is sample size calculated for estimating the population mean? Provide examples

For normal population with known standard deviation, the x% confidence interval for the population mean µ...

For normal population with known standard deviation, the x% confidence interval for the population mean µ has a lower end point (z times the standard error) below the sample mean and a upper end point (z times the standard error) above the sample mean. That is, the x% CI is given as Sample mean ± z *standard error For 95% CI, the value for z is Answer 1Choose...2.581.6451.280.9751.96 For 80% CI, the value for z is Answer 2Choose...2.581.6451.280.9751.96 For 90%...

Question