# Sample Size and Probability

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1 ) Management has asked a lab to produce accurate results at the 88% level for a first time experiment. the management wants the final error to be within 1/10th of the sample standard deviation. Find the sample size.

2) A sample of 16 women had a mean score of 275 and a variance value of 360.

A. find both the 955 and 99% confidence intervals. what is the standard error and the maximum error for each?

B. Repeat "a" group of 28 women.

C. Explain the difference in the answers for both confidence levels and both sample size.

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1)

For 88% confidence, z = 1.5548

E = s/8 which means s/E = 8

N = (z * s/E)^2

N = (1.5548 * 8)^2 = 154.71

Minimum sample size required is 155.

2)

(a) (i) 95% confidence interval:

Data:

n = 16

x-bar = 275

s = 18.9737

% = 95

Standard Error, SE = s/√n = 4.7434

Degrees of freedom = 15

t- score = 2.1314

Maximum Error = Width of the confidence interval = t * SE = 10.1104

Lower Limit of the confidence interval = x-bar - width = 264.8896

Upper Limit of the confidence interval ...

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