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# Sampling/Confidence Intervals

I would like to have the following sample questions answered in EXCEL format, so that I can see the formulas used.

1. The mean score of a college entrance exam is 500; the standard deviation is 75. The score are normally distributed. What percent of the students scored below 320?

2. On a very hot summer day, 5 percent of the production employees at Midland State Steel are absent from work. The production employees are to be selected at random for a special in-depth study on absenteeism. What is the probability of selecting 10 production employees at random on a hot summer day and finding the none of them are absent?

3. For the normal distribution, the mean plus and minus 1.96 standard deviations will include about what percent of the observations?

4. Sweetwater and Associates write weekend trip insurance at a very nominal charge. Records show that the probability that a motorist will have an accident during the weekend and file a claim is 0.05.

Suppose they wrote 20 policies for the coming weekend, what is probability that exactly two claims will be filed?

5. Chances are 50-50 that a newborn baby will be a girl. For families with 5 children, what is the probability that all the children are girls?

#### Solution Summary

The solution gives detailed on solving 5 questions using either normal distribution or binomial distribution using Excel.

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