1) Population proportion = 0.75;

sample size = 70

What is the sample proportion's Standard Error?

Tip: Sqrt(*(1-)/n)

5 decimals. (ex. if the answer is 7.8946%, write as 0.07895

2) The same question: Population proportion = 0.75; sample size = 70

What is the Z-value if less than 70% rate the food as excellent?

Tip: Pbar = 0.70Z = (Pbar -)/Standard Error

3 decimals.

3) Finally: same questions: Population proportion = 0.75; sample size = 70

What is the probability that less than 70% rate the food as excellent?

Tip: P(Pbar < 0.70) = P(Z

4 decimals.

4) Now, the company increased the sample size to 300 customer survey,

Same questions: Population proportion = 0.75; sample size =300

What is the probability that less than 70% rate the food as excellent?

Tip: P(Pbar < 0.70) = P(Z

4 decimals.