Question

The time it takes to complete one biology experiment is normally distributed with known standard deviation...

The time it takes to complete one biology experiment is normally distributed with known standard deviation of 20 minutes. A random sample of 64 experiments in the science school in UCLA had a mean time of 75 minutes. Find the standard error, margin of error, and the upper and lower confidence limits of a 95% confidence interval for the population mean, m.

Homework Answers

Answer #1

Solution :

Given that,

Sample size = n = 64

Z/2 = 1.96

Standard Error = /n

= 20 / 64

Standard Error = 2.5

Margin of error = E = Z/2* Standard Error

= 1.96 * 2.5

E = 4.9

At 95% confidence interval estimate of the population mean is,

- E < < + E

75 - 4.9 < < 75 + 4.9

70.1 < < 79.9

Lower confidence limits = 70.1

Upper confidence limits = 79.9

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