Stats Quiz ***Professor Anthony ONLY***

Name

1. Assume two people are randomly selected and also assume that

Birthdays occur on the days of the week with equal frequencies.

a. Find the probability that two people are born on the same

Day of the week.

b. Find the probability that the two people are both born on

Monday.

2. Doors have a height ot 6 feet 8 inches or 80 inches. Given that

the heights of men are normally distributed with a mean of 69.0

inches with a standard deviation of 2.8 inches, find the

percent of men who can fit through the doorway without

bending over or bumping their heads. [hint: use normalcdf on

your calculator with these numbers: a negative value

representing the left side of the area under the normal curve,

a number for the right side of the area, the mean, and the

standard deviation]

3. In Baltimore's Inner Harbor a water taxi sank, possibly because it

was overloaded. The mean weight of men is 172 pounds with a

standard deviation of 29 pounds. Find the probability that 20

randomly selected men will have a mean weight that is greater

than 175 pounds (this would overload the taxi which has a maximum load of 3500 pounds. [hint: use the same normalcdf but with the area such that the left bound is 175 and the right bound is +9999.

4. The weights of 20 randomly selected silver dollar coins has a

Mean weight of 8.071 g, and a standard deviation of 0.0411 g.

Use the TInterval on your calculator (press Stat then tests) to find the 95% confidence interval. What is the error bound?