Is It a Probability Distribution?

A group of 625 students has a mean age of 15.8 years with a standard deviation of 0.6 years. The ages are normally distributed. What is the probability that a randomly selected student is older than 16.5 years old?

• 0.864

• 0.879

• 0.121

• None of these

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?

• .0057

• .025

• .345

• .781

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?

• .236

• .429

• .571

• .614

It is the mathematical function that gives the probabilities of occurrence of different possible outcomes for an experiment.

Supposed two coins are tossed consecutively and we are interested in the number of heads that will come out. Determine the values of the random variable H (number of heads).

• 0,2,3,4

• 0,1,2,3

• 0,1,2

• 0,1,2,3,4

Which of the following are the properties of a Normal Probability Distribution.

• The distribution curve is bell - shaped.

• The curve is symmetric about its center, the mean.

• The mean, the median, and the mode coincide at the center.

• The area under the curve is 1 or 100%

• The tails of the curve is asymptotic to the base line.

If you select one adult at a random from this community, what is the probability that the adults is employed as part -time?

TRUE or FALSE: The standard normal distribution of a random variable is a normal distribution with mean =0 and standard deviation =1.

• TRUE

• FALSE

The following table represents the probability distribution X, the employment status of adults in a city.

What is the probability that the adults isn't retired?