Stat Homework

6.4 Homework

Pg 363-367 #2, 3, 5, 7, 8, 11, 12, 13, 17, 19, 31, 33, 37, 39, 43, 45, 47, 51, 53, 59, 61, 63, 67, 71, 79, 87, 115, 121, 122

2. In the graph of a probability distribution, what is represented on the number line?

3. How is probability represented in the graph of a continuous probability distribution?

5. True or false: The graph of the uniform distribution is always shaped like a square.

7. What is the value for the mean of the standard normal distribution?

8. What is the value for the standard deviation of the standard normal distribution?

Assume that X is a uniform random variable, with left endpoint 0 and right endpoint 100. Find the following probabilities:

11. P(50 < X <100)

12. P(50 ≤ X ≤ 100)

13. P(25 < X < 90)

Assume that X is a uniform random variable, with left endpoint -5 and right endpoint 5. Compute the following probabilities:

17. P(0 ≤ X ≤ 5)

19. P(- 5 ≤ X ≤ - 4)

Birth weights are normally distributed with a mean weight of µ = 3285 grams and a standard deviation of ơ = 500 grams.

31. What is the probability of a birth weight equal to 3285 grams?

33. What is the probability of a birth weight of at least 3285 grams?

Find the area under the standard normal curve that lies to the left of the following:

37. Z = 1

39. Z = 3

43. Z = - 0.2

Find the area under the standard normal curve that lies to the right of the following:

45. Z = 1.27

47. Z = - 3.01

Find the area under the standard normal curve that lies between the following:

51. Z = 2 and Z = 3

53. Z = - 1 and Z = 0

Find the indicated probability for the standard normal Z:

Draw the graph. Find the area using the Z table or technology.

59. P(Z = 0)

61. P(Z < 10)

63. P(Z < - 2.17)

67. P(- 3.05 < Z < - 0.94)

Find the z-value with the following area under the standard normal curve to its left. Draw the graph, and then find the z-value.

71. 0.3336.

Find the z-value with the following area under the standard normal curve to its right. Draw the graph, and then find the z-value.

79. 0.8078

Find the values of z that mark the boundaries of the indicated area:

87. The middle 80%

115. Nicholas took a standardized test and was informed that the z-value of the test score was 1.0. Find the percentages of test takers that Nicholas scored higher than.

121. Find the following areas without using the z table or technology. The area to the left of z = -1.5 is 0.0668.

a. Find the area to the right of z = 1.5.

b. Find the area to the right of z = - 1.5.

c. Find the area between z = - 1.5 and z = 1.5.

122. Find the following areas without using the z table or technology. The area to the right of z = 2.7 is 0.0035.

a. Find the area to the left of z = 2.7.

b. Find the area to the left of z = - 2.7.

c. Find the area between z = - 2.7 and z = 2.7.

Stat 104 6.4 HW Page 1 of 2

Instructor J Hodgson