Sampling Distribution on Mean and Proportion

What is the mean of the sampling distribution?

• 200

• 25

• 20

• 5

• 4

The mean and standard deviation of a population are 200 and 20, respectively. Sample size is 25.

What is the standard deviation of the sampling distribution?

• 200

• 25

• 20

• 5

• 4

Researches found that boys playing high school football absorb an average of 355 hits to the head with a standard deviation of 80 hits during a season. What is the probability on a randomly selected team of 48 players that the average number of head hits per player is between 340 and 360?

• Approximately 0.0418

• Approximately 0.09

• Approximately 0.57

• Approximately 0.67

• Approximately 0.9582

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?

• Approximately 0.15

• Approximately 0.43

• Approximately 0.57

• Approximately 0.85

It is known that the mean of the population of unicorns equals 1000, and the standard deviation equals 25. In a group of 20 randomly selected unicorns, what is the standard deviation of the sampling distribution?

• 25

• 1.25

• 5.59

• 40

• 4

The weights of unicorns are known to have a mean of 1000 and a standard deviation of 25. What is the probability that the average weight of 25 randomly selected unicorns is greater than 1010 pounds?

• 65.54%

• 97.72%

• 2.28%

• 34.46%

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?

• 0.0057

• 0.025

• 0.345

• 0.781

• 0.9943

The mean of the sample means is equal to the mean of the population.

• True

• False

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

• The Population

• The sample

• The sampling distribution (mean)

• The sampling distribution (proportion)

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?

• 0.866

• 0.8078

• 0.1922

• 0.2743

• 0.7257