Finding Probabilities

The mean number of accidents a week at a company is 6.4 with a standard deviation of 1.5.  What proportion of weeks would you expect to have less than 5 accidents?

• 0.6915

• 0.1762

• 0.8238

• -0.93

The mean number of accidents a week at a company is 6.4 with a standard deviation of 1.5.  What proportion of weeks would you expect to have more than 7 accidents?

• 0.3446

• 0.2856

• 0.4

• 0.6554

The mean GPA of students in a course at UCDavis is 3.2 with a standard deviation of 0.3. What percent of students in the course have a GPA between  2.9 and 3.8?

• 81.5%

• 47.5%

• 68%

• 95%

Charlie is 90% accurate at foul shots. Suppose in a single game he had the chance to shoot 14 times. What is the probability that…

He makes fewer than 12 shots? Round to the nearest hundredth.

Charlie is 90% accurate at foul shots. Suppose in a single game he had the chance to shoot 14 times. What is the probability that…

He makes no more than 10 shots? Round to the nearest hundredth.

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

• The Population

• The Sample

• The Sampling Distribution

A distribution showing the sample means of all sample of size n of a population is called

• Normal Distribution

• Binomial Distribution

• Sampling Distribution

• Uniform Distribution

The Gallup Poll asked a random sample of 1785 adults whether they attended church during the past week.  Let p-hat be the proportion of people in the sample who attended church.  A newspaper report claims that 40% of all U.S. adults went to church last week.  Suppose this claim is true. 
What is the mean of the sampling distribution of p-hat?

• 0.4

• 0.44

• 0.56

• 0.6

28% of all Suncoast students believe in Santa. You take a sample of 50 students and find that 15 of them believe in Santa. What does 15/50 represent?

• n

• P

• phat

• standard deviation

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

• 16

• 25

• 4