SOLUTION: 1. Convert x = 70 to z-score if Normal Distribution has mean = 50 and Standard Deviation = 10. A) 0.5 B) 1.0 C) 1.5 D) 2.0 Question 2 1. Find

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Question 879203: 1.
Convert x = 70 to z-score if Normal Distribution has mean = 50 and Standard Deviation = 10.
A)
0.5

B)
1.0

C)
1.5

D)
2.0

Question 2
1.
Find x-value for z-score=1.5 if Normal Distribution has mean = 50 and Standard Deviation = 10.
A)
65

B)
60

C)
55

D)
45

Question 3
1.
Using the Appendix table for standard normal distribution
find the area under the curve to the left of z = -1.25
A)
0.1432

B)
0.3461

C)
0.4574

D)
0.1056

Question 4
1.
Use Appendix Table for standard normal distribution
to find area under the curve to the right of z = 2.00
A)
0.4572

B)
0.0228

C)
0.1462

D)
0.5431

Question 5
1.
Use standard normal distribution table (Appendix Table II) to find
the probability that z is between -1.5 and 1.5: P(-1.5 < z < 1.5)
A)
0.9332

B)
0.4268

C)
0.8664

D)
0.0559

Question 6
1.
For Normal distribution with mean 50 and standard deviation 10
find probability that x will be less than 35: P(x < 35).
A)
0.8893

B)
0.2101

C)
0.1020

D)
0.0668

Question 7
1.
Household Income has Normal Distribution with average 44,000
and Standard Deviation = 20,000. Find the probability that
Household Income is GREATER than 56,000.
A)
0.1245

B)
0.2743

C)
0.4184

D)
0.6105

Question 8
1.
Number of students who graduate College every year is Normal Distribution
with mean = 400 and standard deviation 50. Find probability that this year
between 300 and 500 students will graduate College.
Tip: Convert 300 and 500 to z values, use Appendix Table II
and then apply rule: P(a < x < b) = P(x < b) - P(x < a)
A)
0.52

B)
0.65

C)
0.95

D)
0.81

Question 9
1.
Sample size is 64, sample mean is 50.
Assuming the population standard deviation is ?=16,
construct 95% confidence interval for population mean.
For z factor use z?/2 = 2
A)
from 46 to 54

B)
from 40 to 60

C)
from 50 to 64

D)
from 35 to 65

1 points
Question 10
1.
For sample mean x = 80, sample size n = 36 and sample standard deviation s = 24
find 90% confidence interval for population mean.
This is the case when population standard deviation is not known.
Use formula on page 328 with t-value.
Find t-value in Appendix Table IV.
Tip: For confidence level 90% ? = 1 - 0.90 = 0.10, ?/2 = 0.10/2 = 0.05
So, in Table IV use column t0.05 and line with df = n - 1 = 36 - 1 = 35.
A)
from 65.48 to 95.86

B)
from 75.44 to 82.16

C)
from 73.24 to 86.76

D)
from 70.18 to 88.65

Answer by ewatrrr(24785) (Show Source):
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Question 1: z = 2 *Note:
Question 2: x = 65
Question 3: P(z < -1.5)= .0668
Question 4: P(z > 2)= .0228
Question 5: P(-1.5 < z < 1.5) = .9332 -.0668
Question 6: P(x < 35) = P(z < -1.5)= .0668 *Note:
Below: z = 0, z = � 1, z= �2 , z= �3 are plotted.
The area under the normal curve to the left of a particular z-value = P(z)
Note: z = 0 (x value: the mean) 50% of the area under the curve is to the left and 50% to the right