# statistics

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a. A random sample of 25 was drawn from a normal distribution with a standard deviation of 5. The sample mean is 80. Determine the 95% confidence interval estimate of the population mean.

• statistics -

Formula:
CI95 = mean + or - 1.96(sd/√n)

sd = standard deviation
n = sample size

Substitute the values from your problem into the formula and calculate.

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