Normal Distributions and Central Limit Theorem

The amount of fuel used by jumbo jets to take off is normally distributed with a mean of 4000 gallons and a standard deviation of 125 gallons. What is the probability that the mean number of gallons of fuel needed to take off for a randomly selected sample of 40 jumbo jets will be less than 3950 gallons?

• .00571

• .655

• .345

• .994

Suppose the teenagers that attend public high schools get an average of 5.7 hours of sleep each night with a standard deviation of 1.7 hours. What is the probability that a randomly selected group of 35 high school students get more than 6 hours of sleep each night?

• .430

• .148

• .281

• .087

State whether you would use the central limit theorem or the normal distribution:
The weights of the eggs produced by a certain breed of hen are normally distributed with mean 65 grams and standard deviation of 5 grams.
What is the probability that the average weight of a dozen eggs selected at random will be more than 68 grams? 

• Central Limit Theorem

• Normal Distribution

A population of students have a mean age of 15.8 years with a standard deviation of 0.6 years. The ages are normally distributed. What age represents the 90th percentile?

• 17.196

• 15.0311

• 16.569

• None of these

State whether you would use the central limit theorem or the normal distribution:
The weights of the eggs produced by a certain breed of hen are normally distributed with mean 65 grams and standard deviation of 5 grams.
What is the probability that one egg selected at random from a hen house will weigh more than 68 grams?

• Central Limit Theorem

• Normal Distribution

The normal curve is symmetrical about the mean.

• True

• False

Red blood cell counts of women are normally distributed with a mean of 4.577 and a standard deviation of 0.382. Find the probability that one randomly selected woman has a red blood cell count above 5.4.

• 0.150

• 0.0156

• 0.215

• 0.0237

• 400

• 40

• 25

• 8

• 400

• 40

• 25

• 8

These symbols represent the mean and standard deviation for which of the following?

• The Population Distribution

• The Sample Distribution

• The Sampling Distribution

• The Binomial Distribution