Question

A random sample of size 65 has sample mean 78 and sample standard deviation 7.5. Find...

A random sample of size 65 has sample mean 78 and sample standard deviation 7.5. Find a 98% confidence interval for µ.

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Answer #1

A random sample of size 65 has sample mean 78 and sample standard deviation 7.5. Find a 98% confidence interval for µ.

Table value t at 65-1 = 64 DF is 2.3860

98% CI =(75.7804, 80.2196)

Confidence Interval Estimate for the Mean

Data

Sample Standard Deviation

7.5

Sample Mean

78

Sample Size

65

Confidence Level

98%

Intermediate Calculations

Standard Error of the Mean

0.9303

Degrees of Freedom

64

t Value

2.3860

Interval Half Width

2.2196

Confidence Interval

Interval Lower Limit

75.7804

Interval Upper Limit

80.2196

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