A random sample of 93 observations produced a mean

1. A random sample of 93 observations produced a mean x=25.5 and a standard deviation sequals=2.4.

a. Find a​ 95% confidence interval for μ.

b. Find a​ 90% confidence interval for μ.

c. Find a​ 99% confidence interval for μ.

2. The mean and standard deviation of a random sample of n measurements are equal to 34.4 and 3.6​, respectively.

a. Find a 90​% confidence interval for μ if n=121.

b. Find a 90​% confidence interval for μ if n=484.

c. Find the widths of the confidence intervals found in parts a and b. What is the effect on the width of a confidence interval of quadrupling the sample size while holding the confidence coefficient​ fixed?

3. If you wish to estimate a population mean with a margin of error ME=0.23 using a​ 95% confidence interval and you know from prior sampling that σ2 is approximately equal to 7.3​, how many observations would have to be included in your​ sample?

The number of observations that would have to be included in your sample is

Here’s the SOLUTION

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