A researcher studying public opinion of proposed Social Security changes and asks a random sample of adult Americans whether or not they support the proposed changes. To say that the distribution of the sample proportion of adults who respond yes, is approximately normal, how many adult Americans does the researcher need to sample in the following cases (a) if 37% of all adult Americans support the changes?
(b) 25% of all adults Americans support the changes?

Complete question is;

A researcher studying public opinion of proposed Social Security changes and asks a random sample of 30 adult Americans whether or not they support the proposed changes. To say that the distribution of the sample proportion of adults who respond yes, is approximately normal, how many adult Americans does the researcher need to sample in the following cases

(a) if 37% of all adult Americans support the changes?

(b) 25% of all adults Americans support the changes?

A) 13 adults

B) 23 adults

Step-by-step explanation:

A) We are given;

p = 37% = 0.37

Since we are told that this is an approximately normal distribution, we will use the formula;

np(1 - p) ≥ 10

Thus;

0.37n(1 - 0.37) ≥ 10

n ≥ 10/(0.63 × 0.37)

n ≥ 42.9

We need a whole number, thus n = 43

From the question, we have already 30 adults , so the required number of adults are; 43 - 30 = 13 adults

B) We are given;

p = 25% = 0.25

Since we are told that this is an approximately normal distribution, we will use the formula;

np(1 - p) ≥ 10

Thus;

0.25n(1 - 0.25) ≥ 10

n ≥ 10/(0.75 × 0.25)

n ≥ 53.33

n ≈ 53

From the question, we have already 30 adults , so the required number of adults are; 53 - 30 = 23 adults

answer: city needs 2.4 inches of rainfall more to match the record of 40 inches.

step-by-step explanation:

since we have given that

total annual rainfall a city record = 40 inches

this year, total rainfall recorded = 37.6 inches

number of inches of rainfall   is needed to match the record of 40 inches is given by

hence, city needs 2.4 inches of rainfall more to match the record of 40 inches.

graph them on a graphing calculator, press 2nd trace. select intersect. hit enter until it says answer. ti 84 works best

step-by-step explanation: