Statistics Homework/Quiz

Name: ___________________________________ Date: ______________

 

Statistics Exam 1

 

**THIS PAGE IS NOT REQUIRED FOR YOU TO COMPLETE.**

 

PLEASE BOX and/or HIGHLIGHT YOUR ANSWERS.

Use this page as an easy way to keep track of your data. To make it simple I labeled the variables X and Y.

MW=X

TTh=Y

 

1. Professor Alvarez’s Study

MW=X nX = _________ x̅ =________ s2x =________ sx =SD= ________

TTh=Y nY = ________ y̅ =________ s2y =________ sy =SD= ________

 

Class	Final Grades	∑
X
Y

 

 

Both Classes (MTWTh) NX = _________ x̅ =________ s2x =________ sx =SD= ________

 

Both Classes

Final Grades

∑

X

 

 

 

Name: ________________________________________ Date: ______________

 

 

Statistics Exam 1

Chapter 1, 2, & 3

1. Indicate whether the following variables are qualitative (QL) or quantitative (QU):

a. Favorite color ____

b. Current Occupation ____

c. Number of extra credit problems you solved ____

d. Number of students in our class ____

e. Exam Grades ____

 

2. Indicate whether the following variables are discrete (D) or continuous (C):

a. Height of your classmates. ____

b. Number of hours in a day. ____

c. Number of children. ____

 

3. Match each example with a Scale of Measurement from above (HINT: Think about your descriptions above and there are two examples for each scale): Label as N, O, I, or R.

a) Eye Color ____

b) Class rank____

c) Time ____

d) Money in your Bank Account ____

e) Weight ____

f) Gender ____

g) Money in your Wallet ____

h) Food Preferences ____

 

4. Briefly DESCRIBE and DRAW the following

a. Symmetric Distribution

 

 

b. Bimodal Distribution

 

 

c. Unimodal Distribution

 

 

d. Negatively Skewed Distribution

 

 

e. Positively Skewed Distribution

Variable	Value	∑
X	2	3	6	7	10
Y	4	4	8	9	11
XY

5. For the following please use

 

a. X2 =

b. Y5 =

c. XY1 =

 

b. Calculate

 

4

2

 

i. ∑XY

 

 

ii. (∑XY)2 + (∑X ) (∑Y )

 

iii. ∑X2

 

iv. (∑Y)2

 

 

6. Professor Alvarez was interested in studying the days that students took a class and their final grades. The following data represents students from his MW and TTh Psychology classes and their final grades.

 

MW	72	72	77	84	86	88	92	101	103
TTh	66	70	82	84	86	86	90	91	91

 

 

Please use the information from the question and table to answer and calculate the following.

a) What is the dependent variable? Is it qualitative or quantitative? Is it discrete or continuous? What is its level of measurement?

 

 

 

 

b) What is the independent variable? Is it qualitative or quantitative? Is it discrete or continuous? What is its level of measurement?

 

 

 

 

 

c) What is the population? ______________________________

 

d) What is the sample? _________________________________

 

e) Was this a Random Sample? If so why? If not describe one of the sampling methods from the book and how we can use it to get a better sample.

 

 

 

 

 

f) What type of research design was this? Explain.

 

 

 

 

 

g) If we calculated the mean final grade of Professor Alvarez’s students and only used his sample, would this be a descriptive or inferential statistic? Why?

7. Complete the following using the data from the Professor Alvarez’s study. You can use the table on the last page if necessary.

 

Create a Frequency Distribution of

 

i. Class Day(Make sure to label the distribution)

 

 

 

 

 

ii. Final Letter Grades for both classes. (Make sure to label the distribution)

A = 90-100+ B = 89-80 C = 79-70 D =69-60 F =59-0

 

 

 

 

 

 

 

Create a back-to-back Stem-and-Leaf Display for the MW and TTH Classes

 

MW	STEM	TTH

 

 

 

 

 

 

 

 

.

 

 

Create a histogram for the following. (Use intervals of 10)

 

ii. Histogram for all students (MW and TTh combined)

 

8. Calculate the following using the data from the Professor Alvarez’s study.

USE THE DATA SHEET IF NECESSARY. SHOWING WORK IS NOT NECESSARY BUT CAN HELP WITH RECEIVING PARTIAL CREDIT.

 

Write out the following equations in mathematical notation.

 

Median Location=

 

 

 

______________________________________________________________________________

a.

 

 

3

 

 

b. For MW

 

i. nX = ______

 

ii. = ______

 

iii. Median = ______

 

iv. Mode = ______

 

v. Range = ______

 

vi. IQR = ______

 

vii. = ______

 

viii. = ______

 

 

c. For TTh

 

i. nY = ______

 

ii. = ______

 

iii. Median = ______

 

iv. Mode = ______

 

v. Range = ______

 

vi. IQR = ______

 

vii. = ______

 

viii. = ______

 

 

d. For All Students

(MW and TTh Combined)

 

i. N = ______

 

ii. = ______

 

iii. Median = ______

 

iv. Mode = ______

 

v. Range = ______

 

vi. IQR = ______

 

vii. = ______

 

viii. = ____

9. Using the data that you calculated, answer the following

e. For Professor Alvarez’s study

i. Which class did better? How can you tell? What statistic did you use?

 

ii. Who had a wider deviation? What statistic did you use? What does this mean?

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