STATS 250 Study Guide - Final Guide: Normal Distribution, Mean Absolute Difference, Analysis Of Variance

(1 point) A random sample of 130 observations is selected from a binomial population with unknown probability of success p. The computer value of is 0.64.

    (1) Test : : p = 0.65 against : p > 0.65. Use α= 0.05.

test statistic z =

critical z score

The final conclusion is 

⭕ A. We can reject the null hypothesis that p = 0.65 and accept that p is > 0.65.

⭕ B. There is not sufficient evidence to reject the null hypothesis that p = 0.65.

    (2) Test : p = 0.5 against :p < 0.65. Use α = 0.01.

test statistic z =

critical z score

The final conclusion is 

⭕ A. We can reject the null hypothesis that p = 0.5 and accept that p is < 0.5.

⭕ B. There is not sufficient evidence to reject the null hypothesis that p = 0.5.

   (3) Test : p = 0.55 against : p ≠ 0.55. Use α = 0.01.

test statistic z =

positive critical z score

A sample of 36 observations is selected from a normal population. The sample mean is 12, and the population standard deviation is 3. Conduct the following test of hypothesis using the 0.01 significance level: H0: μ ≤ 10 H1: μ > 10

a. Is this a one- or two-tailed test?

b. What is the decision rule, Reject H0 when Z > 2.33 or when Z <= 2.33 ?

c. What is the value of the test statistic? (Round the final answer to 1 decimal place.)

d. What is your decision regarding H0? (Reject or Accept) ?

e. What is the p-value, one, zero, or close to zero ? 

Use the following scenario for questions 6 – 8. In 2016-17, the average SAT score of the UVA first year class was 1420 out of 1600. An advisor in the statistics department is interested in determining whether statistics majors from that class have higher SAT scores than the average. He tests H,:µ = 1420 against Hạ: µ > 1420, where u is the mean SAT score for statistics majors from the 2016-17 first year class. In a simple random sample of 30 statistics majors, he finds a sample mean SAT score of 1440 with sample standard deviation of 40.

6. What is the value of the test statistic for this significance test?

a. 0.09

b. 0.5

c. 2.73

d. 20

7. From what distribution is this test statistic?

a. N(0, 1)

b. N(1420, 7.30)

c. t distribution with 29 degrees of freedom

d. t distribution with 28 degrees of freedom

8.) The p-value for this test is 0.005. Which of the following is a proper interpretation of this p- value?

a.There is a 0.5% chance that the null hypothesis is true.

b. If the population mean SAT score really is 1420, there's a 0.5% chance that the sample a. mean SAT score from 30 statistics majors would equal 1440.

c.If the population mean SAT score really is 1420, there's a 0.5% chance that the sample mean SAT score from 30 statistics majors would be 1440 or lower.

d. If the population mean SAT score really is 1420, there's a 0.5% chance that the sample mean SAT score from 30 statistics majors would be 1440 or higher.