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WorksheetsPS22 Quiz 6.2
Total questions: 80
Worksheet time: 3hrs 41mins
What is the total area under the normal curve in a standard normal distribution?
1
2
3
4
For the density curve shown, which statement is true?
The density curve is Normal.
The density curve is skewed right.
At the mean, the height of the curve is 1.
The density curve is symmetric
None of the above is correct.
For the density curve shown, which statement is true?
The mean is greater than the median.
The mean is less than the median.
The mean and median are equal.
The mean could be either greater than or less than the median.
None of the above is correct.
Two measures of center are marked on the density curve shown. Which of the following is correct?
The median is at the yellow line and the mean is at the red line.
The median is at the red line and the mean is at the yellow line.
The mode is at the red line and the median is at the yellow line.
The mode is at the yellow line and the median is at the red line.
.
The mode is at the red line and the mean is at the yellow line.
The density curve shown takes the value 0.5
on the interval 0 ≤ x ≤ 2 and takes the value 0
everywhere else. What percent of the observations lie
between 0.5 and 1.2?
25%
35%
50%
68%
70%
Z=0.27.
z=-1.53 and z=0.
About what percent of the products last between 12 and 15 days?
What is the the total area under the standard normal distribution curve?
100
25
.5
1
If waist sizes are normally distributed, estimate the proportion of teenagers who will have waist sizes greater than 31 inches?
Mensa International is a non-profit organization that accepts only people with IQ score within the top 2%. What level of IQ qualifies one to be a member of Mensa?
Suppose a male long jumper's jump ranked in the 75th percentile. How long was his jump?
About what percent of the products last between 12 and 15 days?
If I tell you that you scored at the 55th percentile on your final exam, you would know:
55% of the class scored the same or worse than you did
You earned a 55% on the exam
You failed the exam
45% of the class scored worse than you did
Find the z-score for 48 given a mean of 50 and a standard deviation of 5.
2.5
-2.5
-0.4
0.4
Find the area under the standard normal curve that lies to the left of z=2.1.
1.79%
-1.79%
98.21%
0.98%
Find the area under the standard normal curve that lies to the right of z=-0.67.
63.42%
74.86%
25.14%
50%
Test has a mean of 40 and a standard deviation of 10. What is the percent of people that scored above 62?
1.39%
45.34%
98.41%
22.34%
A continuous random variable is normally distributed with mean 145 and standard deviation is 5. Find P(136<X<140).
0.8054
0.8772
0.1228
0.1587
The width of the curve is determined by the _____________________.
Mean
Variation
Standard Deviation
Standard Normal Curve
A standard normal curve is a normal probability distribution that has a standard deviation of ____ and a mean of ____.
1, 0
0, 1
0, 0
1, 1
A normal distribution is symmetric.
True
False
The normal probability distribution is completely described by its mean and ________.
variance
standard deviation
range
mean deviation
The standard normal probability distribution has mean of 0 and a standard deviation of _____.
21
−1
1
−21
Any normal probability distribution can be converted to the standard normal probability distribution by the following formula
z=σX−μ
z=σμ−X
z=σX+μ
z=σXμ
By standardizing a normal probability distribution, we can report the distance of a value from the mean in units of the __________ .
median
standard deviation
variance
mode
The signed distance between a selected value, designated X, and the mean, μ, divided by the standard deviation, σ.
p value
z value
r value
t value
It was reported that the weekly income of Uber drivers followed the normal distribution with a mean of $1,000
and a standard deviation of $100. What is the z value corresponding to to x = $1,000?
1
-1
0
cannot be determined
It was reported that the weekly income of Uber drivers followed the normal distribution with a mean of $1,000
and a standard deviation of $100. What is the z value corresponding to to x = $1,100?
1
-1
0
cannot be determined
The distribution of weekly incomes follows the normal probability distribution, with a mean of $1,000 and a standard deviation of $100. What is the sign of the z value corresponding to an income of $750?
negative
positive
The distribution of weekly incomes follows the normal probability distribution, with a mean of $1,000 and a standard deviation of $100. What is the sign of the z value corresponding to an income of $1,200?
negative
positive
About what percent of the products last between 12 and 15 days?
About what percent of the products last 6 days or less?
Then, 68% of all tires will have a life between ___________ km and __________ km.
Suppose a male long jumper's jump ranked in the 75th percentile. How long was his jump?
Given a mean of 75 and a standard deviation of 7, what percentage of scores are between 75 and 82?
68%
81.5%
16%
34%
Given a mean of 75 and a standard deviation of 7, what percentage of scores are above 82?
34%
81.5%
16%
2.5%
Given a mean of 75 and a standard deviation of 7, what percentage of scores are between 54 and 96?
34%
99.7%
95%
2.5%
Given a mean of 75 and a standard deviation of 7, what percentage of scores are greater than 68?
34%
84%
95%
68%
Given a mean of 75 and a standard deviation of 7, how many students out of 500 would score between 61 and 89?
475
400
340
80
Given a mean of 75 and a standard deviation of 7, how many students out of 500 would score higher than 82?
475
170
237
80
Given a mean of 75 and a standard deviation of 7, how many students out of 500 would score between 75 and 82?
475
170
340
237
Given a mean of 75 and a standard deviation of 7, how many students out of 500 would score between 68 and 82
11
2
340
498
Given a mean of 75 and a standard deviation of 7, how many students out of 500 would score higher than 89?
11
12
36
237
Given a mean of 75 and a standard deviation of 7, how many students out of 500 would score higher than 68?
11
12
420
250
What type of distribution is pictured?
Right skewed
Left skewed
Random
Normal
What is P(x > 27)?
97.5%
84%
13.5%
2.5%
What is P(33 < x < 51)?
84%
68%
81.5%
18.5%
What is P(x < 35)
47.5%
13.5%
84%
16%
What is P(68 < x < 84)?
47.5%
83.85%
84%
87.5%
What is P( x < 88)?
13.5%
2.5%
97.5%
95%
A statistical study calculated that the average cost of used iPhones is $230, with a standard deviation of $25. What is the probability that a select phone from the sample costs between $205 and $280?
81.5%
68%
95%
47.5%
A statistical study calculated that the average usage of smartphones during class is 22 minutes a day, with a standard deviation of 5 minutes. What is the percentage of the people from the study that uses their smartphones less than 27 minutes a day?
34%
16%
84%
95%
A statistical study calculated that the average score on the SAT Exam is 1270, with a standard deviation of 130. What percentage of examinees from the study scored between 1270 and 1530?
84%
68%
97.5%
47.5%
A statistical study calculated that the average time teenagers spend playing app games each day is 3.4 hours, with a standard deviation of 0.7 hours. What is the percentage of teenagers in the study that spends less than 2.7 hours each day on app games?
68%
16%
84%
13.5%
A statistical study calculated that the average speed of bus drivers is 38 mph, with standard deviation of 4 mph. What percentage of bus drivers in the study drive an average speed greater than 46 mph?
97.5%
84%
16%
2.5%
A standard normal curve is a normal probability distribution that has a standard deviation of ____ and a mean of ____.
1, 0
0, 1
0, 0
1, 1
