A95% confidence is given by (15,20) . the interval is based on a sample of size n=25 .

if we want to reduce the margin of error by half, we need to:

a. double the sample size.

b. quadruple the sample size.

b. quadruple the sample size.

Step-by-step explanation:

Given that a 95% confidence is given by (15,20) .

this implies that mean = average of lower and higher bounds of confidence interval =

Margin of error = Upper bound - Mean =

Confidence level = 95%

Critical value = 1.96

Std  error =

Std devition = Std error * sqrt n = 6.3775

If we want to reduce margin of error by half we must get margin of error as 1.25

For that std error for same critical value = 0.63775

Std deviation did not change

So sample size only changed which implies that sample size is 4 times the original

b. quadruple the sample size.

step-by-step explanation:

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step-by-step explanation: