AP Stats Unit 4

What is the probability that a randomly selected girl speaks French?

• 2.14

• .24

• .4

• .8571

In your top dresser drawer are 6 blue socks and 10 grey socks, unpaired and mixed up. One dark morning you pull two socks from the drawer (without replacement, of course!). What is the probability that the two socks match?Hint: try a tree diagram, but be careful with probabilities on the second column of branches.

• 0.075

• 0.375

• 0.450

• 0.500

If P(A) = 0.24 and P(B) = 0.52 and A and B are independent, what is P(A or B)? Hint: Use formula card

• 0.1248

• 0.28

• 0.6352

• The answer cannot be determined

Event A occurs with probability 0.2. Event B occurs with probability 0.8. If A and B are mutually exclusive (disjoint), then

• P(A or B)=1.0

• P(A and B) = 0.16

• P(A and B) = 1.0

• both a. and b. are true

This data is normally distributed.  What percent of the data is in the shaded region?

• 68%
• 95%
• 99.7%
• 50%

If 10 is added to every value in a set of data, what will happen to the value of the mean?

• it will increase by 10
• it will decrease by 10
• it will stay the same
• it will both increase and decrease

If 10 is added to every value in a set of data, what will happen to the value of the standard deviation?

• it will increase
• it will decrease
• it will stay the same
• it will both increase and decrease

In a survey of men in the United States (ages 20-29), the mean height was 69.6 inches with a standard deviation of 3.0 inches. Find the minimum height in the top 22%.

• 69.37 in 
• 67.58 in 
• 73.12 in 

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

95% of students at school weigh between 62 kg and 90 kg.

Assuming this data is normally distributed, what are the mean and standard deviation?

• Mean = 66 kg

  S.D. = 7 kg

• Mean = 76 kg

  S.D. = 7 kg

• Mean = 86 kg

  S.D. = 7 kg

• Mean = 76 kg

  S.D. = 14 kg