Practice Quiz-Lecture 4

Question 1

The central limit theorem describes the distribution of

Answer 1

sample mean

Question 2

To obtain an 80% confidence interval for the population mean of triglyceride levels using a sample of n = 20 individuals, the critical value is

Answer 2

1.328

Question 3

To obtain an 80% confidence interval for the population mean of triglyceride levels, researchers sample n = 25 individuals and obtained a sample mean triglyceride level of 120 mg/dL. The population standard deviation of 5 mg/dL. The standard error of the distribution of the sample mean is

Answer 3

1 mg/dL
-standard error of the sample mean of triglyceride level = standard deviation of triglyceride level / square root of n.

Here standard deviation of triglyceride level = 5 and n = 25. Hence, standard error = 5 / square root of 25 = 5/5 = 1.

Question 4

To test whether the average triglyceride level in the population of United States (denoted mu) is below 145 mg/dL, researchers sample n = 25 individuals and obtained a sample mean triglyceride level of 120 mg/dL with standard deviation of 5 mg/dL. The null hypothesis is

Answer 4

H0: mu = 145 mg/dL

Question 5

To test whether the average triglyceride level in the population of United States (denoted mu) is below 145 mg/dL, researchers sample n = 25 individuals and obtained a sample mean triglyceride level of 120 mg/dL with standard deviation of 5 mg/dL. The critical value at alpha = 0.05 is

Answer 5

2.064

Question 6

Type I error is the probability that:

Answer 6

H0 is rejected when H0 is actually true

Question 7

When rejecting a null hypothesis H0: mu = mu0 against an alternative hypothesis HA: mu not equal to mu0 using a test statistic T, we reject H0 when

Answer 7

Absolute value of T is greater than the critical value

Question 8

P-value is

Answer 8

Probability of observing the test statistic T or something more extreme under the null hypothesis

Question 9

When testing hypothesis about proportions

Answer 9

The standard error is calculated using the proportion under the null hypothesis

Question 10

When testing hypothesis about proportions, obtain the critical value from

Answer 10

Always obtain from a standard normal distribution, regardless of n