Question

1. In a random sample of 58 people aged 20-24, 22.7% were smokers. In a random sample of 110 people aged 25-29, 29.5% were smokers. Calculate the margin of error for a 95% confidence interval that can be used to estimate the difference between the population proportions p₁ − p₂ of the smokers in these age groups.

Show your answer in decimal form, rounded to three decimal places.

2. Confidence interval for the difference between population proportions.
(Assume that the samples are randomly selected and independent.)


Sample statistics: x ₁ = 36, n ₁ = 64 and x ₂ = 47, n ₂ = 71;
Construct a 95% confidence interval for the difference between population proportions p₁ – p₂

Select one:

a. 0.368 < p₁ – p₂ < 0.757

b. -0.263 < p₁ – p₂  < 0.064

c. -0.294 < p₁ – p₂ < 0.757

d. 0.399 < p₁ – p₂  < 0.726

3. As a result of running a simple regression on a data set, the following estimated regression equation was obtained:

      = 9.7 + 13.4x

Furthermore, it is known that SST = 622, and SSE = 150.

Calculate the correlation coefficient R; round your answer to three decimal places

Answer 1