Question

In: Statistics and Probability

Parents of potential WKU students often express an interest in making sure their child can graduate...

Parents of potential WKU students often express an interest in making sure their child can graduate in 4 years. To do so, students must complete an average of 15 credit hours per semester. A random sample of 250 students at WKU finds that these students take a mean of 14.7 credit hours per semester with a standard deviation of 1.9 credit hours. Assume the sample standard deviation is equal to the population standard deviation. Estimate the mean credit hours taken by a student each semester using a 95% confidence interval. Round to the nearest thousandth. (Note that the options give the answer in the format of sample mean +/- the margin of error).

		14.7 ± .171
		14.7 ± .236
		14.7 ± .015
		14.7 ± .011

Solutions

Expert Solution

Now, we estimate the mean credit hours taken by a student each semester using a 95% confidence interval.

Since we assume that sample standard deviation as population standard deviation so we use Z-critical value to estimate the 95% CI.

Given that,

Sample Mean = 14.7 and Population Standard Deviation = 1.9 and Sample Size = 250

Level of significance:-

Critical Value:-

[ Value are getting from Z-table ]

Margin of Error:-

Now we put the value of , , and we get,

[ Round to the nearest thousandth ]

95% Confidence Interval For Population Mean:-

Now we put the value of MOE and and we get,

i.e. 95% confidence interval for population mean is given by,

Answer:- Correct answer is " 2nd Option "

orchestra answered 1 year ago

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