Soon after he took office in 1963, President Lyndon Johnson was approved by 160 out of a sample of 200 Americans. With growing dissatisfaction over his Vietnam policy, by 1968 he was approved by only 70 of 200 Americans.

Q1 )Find the 95% confidence interval for the percentage of all Americans who approved of Johnson in 1963.

Group of answer choices

1963(0.745,0.855)

1963(0.8,0.35)

1963(0.35,0.855)

No answer provided

Q2) What is the 95% confidence interval for the change in approval?

Group of answer choices

[0.364, 0.536]

[0.234,0.453]

[0.745,0.855]

[0.223,0.789]

Q3) The evidence supports that the approval rate is decreased.

Group of answer choices

True

False

Q4) At a large university, independent random samples of in-state and out-of-state students yield the following summary statistics for GPA:In-stateOut-of-stateX=2.6X=2.9s=0.5s=0.3n=8n=11

Construct a 95% confidence interval for the difference in population means, assuming that the population variances are equal.

Group of answer choices

12(0.3,0.1)

12(0.40.2)

12(0.7,0.1)

12(-0.7,0.1)

Q5)It can be concluded that on average out-of-state students have higher GPA than in-state students

True

False

Q6)As a development economist, you are interested in whether individuals in country A have a lower mean income than those in country B. You have available independent random samples of size 50 each from the two populations. In these samples,

XA=$500sA=$200XB=$600sB=$300

Assuming the population variances are equal, find the p-value and test the hypotheses

H0:BA=0

HA:BA>0

Q7)The pooled variance estimate sp2 calculated from this data is

Group of answer choices

35,000

55,000

65,000

45,000

Q8) What is the p-value?

Group of answer choices

0.04

0.05

0.026

0.01

Q9) What does p-value tell you about the test?

Group of answer choices

I would reject the null hypothesis of equality of means at any level greater than the p-value .

I would reject the null hypothesis of equality of means at any level less than the p-value .

Based on the data, the probability of the mean income of the two countries to be the same is the less than the p-value.

Based on the data, the probability of the mean income of the two countries to be the same is the greater than the p-value.