Download Statistics Test 1 1. Suppose that a Normal model described student

Statistics Test 1
1.
Suppose that a Normal model described student scores in a history class. Parker has a
standardized score (z-score) of +2.5. This means Parker
a.
is 2.5 points above average
b.
is 2.5 standard deviations above average for the class
c.
has a standard deviation of 2.5
d.
has a score that is 2.5 times the average for the class
2.
The change in scales makes it hard to compare scores on the 1994 math SAT (mean 470, standard
deviation 110) and the 1996 math SAT scores (mean 500, standard deviation 100). Jane took the
SAT in 1994 and scored 500. Her sister took the SAT in 1996 and scored 520. Who did better on
the exam, and how can you tell?
a.
Colleen – she scored 20 points higher than Jane
b.
Colleen – her standard score is higher than Jane
c.
Jane – her standard score is higher than Colleen’s
d.
Jane – the standard deviation was bigger in 1994
3.
The distribution of heights of students in a large class is roughly Normal. Moreover, the average
height is 68 inches, and approximately 95% of the heights are between 62 and 75 inches. Thus,
the standard deviation of the height distribution is approximately equal to
a.
2
b.
3
c.
6
d.
9
e.
12
4.
The five number summary for scores on a statistics exam is 11, 35, 61, 70, 79. In all, 380 students
took the test. About how many had scores between 35 and 61?
a.
26
b.
76
c.
95
d.
190
e.
None of these
5.
The mean salary of all female workers is $35,000. The mean salary of all the male workers is
$41,000. What is true about the mean salary of all workers?
a.
It must be $38,000.
b.
It must be larger than the median salary.
c.
It could be any number between $35,000 and $41,000.
d.
It must be larger than $38,000.
e.
It cannot be larger than $40,000.
6.
A reporter wishes to portray baseball players as overpaid. Which measure of center should he
report as the average salary of major league players?
a.
mean
b.
median
c.
Either the mean or the median. It doesn’t matter as they will be equal.
d.
Neither the mean nor the median. Both will be much lower than the actual average salary.
e.
The standard deviation should be used.
7.
Which of the following summaries is changed by adding a constant to each data value?
I.
the mean
II.
the median
III.
the standard deviation
a.
b.
c.
d.
e.
I only
III only
I and II
I and III
I, II and III
8.
Which of the following statements is NOT true?
a.
In a symmetric distribution, the mean and median are equal.
b.
The first quartile is equivalent to the 25th percentile.
c.
In a symmetric distribution, the median is halfway between the first and third quartiles.
d.
The median is always greater than the mean.
e.
The range is the difference between the largest and smallest observation in the data set.
9.
For a set of values, suppose the mean is 10 and the standard deviation is 2. If each value is
multiplied by 9 and added by 10, what will the mean and standard deviation be for the new set of
values?
a.
mean 10; standard deviation 2
b.
mean 10; standard deviation 18
c.
mean 100; standard deviation 2
d.
mean 100; standard deviation 18
e.
mean 100; standard deviation 28
10.
If the standard deviation of a distribution is 4, the variance is:
a.
4
b.
2
c.
8
d.
16
e.
0
11.
The following are reading scores from a sample of 4th and 7th grade students.
4th Grade
12
15
36
37
18
39
20
40
20
42
22
25
26
28
29
31
32
35
35
7th Grade
1
12
31
33
15
33
18
33
18
35
20
36
23
23
24
25
27
28
30
30
a.
Make a comparative boxplot Label!
b.
Are there any outliers? How do we know?
12.
The following are times from the Boston Marathon in minutes.
a.
Create a five number summary.
b.
Are there any outliers? How do we know?
13.
The following is a data set of the weights of 18 year old males.
a.
Find the mean and standard deviation.
b.
Which measures of center and spread would you use to represent this data? Why?