Question 1

The mean salary of people living in a certain city is $37500 with a standard deviation of $1733. A sample of 50 people is selected at random from those living in the city.

Find the probability that the mean income of the sample is less than $38000.

Round your answer to 4 decimal places.

Question 2

1pts

The mean salary of people living in a certain city is $37500 with a standard deviation of $2304. A sample of 44 people is selected at random from those living in the city.

Find the probability that the mean income of the sample is within $500 of the population mean.

Round your answer to 4 decimal places.

Question 3

1pts

IQ scores are normally distributed with a mean of 100 and a standard deviation of 15. A sample of 8 people is selected at random.

Find the probability that the mean IQ of people in the sample is greater than 103.

Round your answer to 4 decimal places.

Question 4

1pts

IQ scores are normally distributed with a mean of 100 and a standard deviation of 15. A sample of 19 people is selected at random.

Find the probability that the mean IQ of people in the sample is within 5 points of the population mean IQ.

Round your answer to 4 decimal places.

Question 5

1pts

The duration of human pregnancies is approximately normally distributed with a mean of 272 days and a standard deviation of 9 days. A sample of 9 pregnancies is selected at random.

Find the probability that the mean duration of the sample is less than 268.

Round your answer to 4 decimal places.

Question 6

1pts

The duration of human pregnancies is approximately normally distributed with a mean of 272 days and a standard deviation of 9 days. A sample of 6 pregnancies is selected at random.

Find the probability that the mean duration of the sample is within 1 days of the population mean duration.

Round your answer to 4 decimal places.

Question 7

1pts

Assume that the height of adult females in the United States is approximately normally distributed with a mean of 64 inches and a standard deviation of 2.78 inches. A sample of 6 such women is selected at random.

Find the probability that the mean height of the sample is greater than 63.1 inches.

Round your answer to 4 decimal places.

Question 8

1pts

Assume that the height of adult females in the United States is approximately normally distributed with a mean of 64.2 inches and a standard deviation of 2.79 inches. A sample of 12 such women is selected at random.

Find the probability that the mean height of the sample is within 0.7 inches of the population mean height.

Round your answer to 4 decimal places.

Question 9

1pts

The mean salary of people living in a certain city is $37500 with a standard deviation of $2290. A sample ofnpeople will be selected at random from those living in the city.

Find the smallest sample sizenthat will guarantee at least a 90% chance of the sample mean income being within $500 of the population mean income.

Round your answer up to the next largest whole number.

Question 10

1pts

IQ scores are normally distributed with a mean of 100 and a standard deviation of 15. A sample ofnpeople will be selected at random.

Find the smallest sample sizenthat would guarantee at least a 95% chance that the mean IQ of the sample is within 3 points of the population mean.

Round your answer up to the next largest whole number.