Exam 1

Question 1

Random irregularity in real life data is ______.

Answer 1

Random irregularity in real life data is Noise/Stochasticity

Question 2

Which of the following is NOT a measure of the center of data?

Mean
Median
Mode
Sum of Squares

Answer 2

Sum of Squares

Question 3

Describe the shape of this distribution

Answer 3

Positively Skewed
Right Skewed

Follow direction of tail

Question 4

A null hypothesis needs to be ______.
Provable
Falsifiable
Accepted

Answer 4

Falsifiable

Question 5

This is an example of a _____ distribution.
Normal
Negatively Skewed
Symmetrical
Positively Skewed

Answer 5

Negatively Skewed

Question 5

Solve the following summation given this data:
20 16 14 15 19

Answer 5

168

We can either multiply each number by 2 before adding them.
40+32+28+30+38 = 168

Or we can add them up and multiply the sum by 2
2(20+16+14+15+19) = 2(84) = 168

Question 6

Name a common measure of dispersion (more than one correct answer)

Answer 6

Range
Variance
Standard Deviation
Average Absolute Deviation

Question 7

You gather the following data on GMU students:
Grade Level
GPA
Major

GPA is what kind of data?
Discrete
Ordinal
Nominal
Continuous

Answer 7

Continuous

Question 8

Grade Level is what kind of data?
Discrete
Ordinal
Nominal
Continuous

Answer 8

Ordinal

Question 9

Answer 9

Question 10

What does mean describe? (Possible answer choices center, spread/dispersion)

Answer 10

Center

Question 11

Variance

Answer 11

Spread/dispersion

Question 12

Average absolute deviation

Answer 12

Spread/dispersion

Question 13

Median

Answer 13

Center
(N+1)/2 = median data point. Example in a data set of 1,3,4,6,7,8,9

N=7

Median = (7+1)/2 = 4th data point = 6

Question 14

Range

Answer 14

Spread/dispersion

Max-Min

Question 15

Mode

Answer 15

Center
Most frequently occurring number. Distributions can be unimodal, bimodal, or multimodal

Question 16

Standard deviation

Answer 16

Spread/dispersion

SDev = (x-mean)^2
(N-1)

Question 17

Answer 17

Question 18

Answer 18

20

1+1
1+2
1+3
1+4
1+5

or (5x1)+(1+2+3+4+5)

Question 19

Answer 19

60

= 2(1+3) +2(2+3)+2(3+3)+2(4+3)+2(5+3)

Question 20

What type of data is blood type?

Answer 20

Nominal

Question 21

What type of data is income level?

Answer 21

Ordinal

Question 22

What type of data is inventory of supplies?

Answer 22

Discrete

Question 23

What type of data is hair color?

Answer 23

Nominal

Question 24

What type of data is temperature?

Answer 24

Continuous

Question 25

What type of data is the number of students per grade level?

Answer 25

Discrete

Question 26

What type of data is continuous?

Answer 26

Monthly expenses

Question 27

What type of data is continuous?

Answer 27

Monthly expenses

Question 28

Answer 28

1/15

Area of the entire probability graph will have to equal 1.0

15 * x = 1

x=1/15=0.06667

Question 29

Answer 29

4*k = probability that student walks 3-7 miles

4*0.06667 = 0.26667

Question 30

What is Poisson distribution used to model? Which parameter(s) do you need?

Answer 30

Rare, independent, random occurrences when the probability of occurring is small

Population mean

it’s appropriate for modeling counts of observations per unit

Question 31

Which distribution would be expected to have the largest population mean and be most accurate to represent the desired outcome?

Answer 31

D