Download STA 2023, Spring 2005

STA 2023, Spring 2005
Sample 3
Round all answers to two decimal places.
A random sample of cars owned by each famlily produced the following table. The X
represents the number of cars owned by each family:
X
4
3
2
1
f
1
4
3
2
1. Calculate the mean. (2 decimal places)
_____2.40_____
2. Calculate the standard deviation. (2 decimal places)
_____0.97_____
3. Calculate the z score for a family with 3 cars. (2 decimal places)
_____0.62_____
Given a mean of 32 and a standard deviation of 4.
4. What is the corresponding z score of value 30? (2 decimal places)
____- 0.50______
5. The z score corresponding to one value is - 2. What is the value? (2 decimal
places)
____24.00______
6. Suppose that the 45th percentile for weight is 70 kg. This means:
(A) 45 percent weigh more than 70 kg
(B) 45 percent weigh less than 70 kg
(C) 55 percent weigh less than 70 kg
(D) 70 percent weigh more than 45 kg
(E) 70 percent weigh less than 45 kg
_____B_______