# STAT 1450 Study Guide - Midterm Guide: Statistical Inference, Pepsodent, Null Hypothesis

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Published on 17 Sep 2020

Department

Statistics

Course

STAT 1450

Professor

Exam 2 Version A

Exam 2 Version A Page 1

Name Mr(s). Key

Recitation Day&Time

STAT 1450 Exam 2 Autumn 2013 - Version A

Circle your recitation TA name fom hi list.

Andrew Bean

Thomas Kilbane

Mark Risser

Hui Yang

Matt Brems

Angus McKay

Andrew Olsen

Your percentage score will be based upon 50 points.

Exercises 1.12. are each worth 2 points and are either multiple choice or fill-in-the-blank.

Circle the best answer.

Use the following information for Questions 1-3:

A study on heart disease classified volunteers by their smoking habits and socio-economic status.

Smoking Habits

Socio-Economic Status (SES)

Current

Former

Total

Upper

52

74

126

Lower

40

34

74

Total

92

108

200

1) What percentage of the volunteers are Current smokers or from the Upper-class?

a) 17%

b) 26%

c) 42%

d) 83%

2) What percentage of the volunteers are neither Current smokers nor from the Upper-class?

a) 17%

b) 26%

c) 42%

d) 83%

3) Which categories of volunteers are disjoint?

a) Volunteers that are Former smokers and the Current smokers.

b) Volunteers from the Upper SES and the Current smokers.

c) Volunteers from the Lower SES and the Current smokers.

d) The aggregate of the SES variable and the Current smokers.

4) Which of the following is not a simple condition associated with statistical inference?

a) Verifying that a data set is from a random sample (or representative of a random sample).

b) Verifying that the population is at least 20 times the size of the sample.

c) Verifying that the population mean, P, is known.

d) Verifying the Normality of the population, or, that the data neither contains heavy skewness

nor outliers.

Exam 2 Version A

Exam 2 Version A Page 2

Use the following information for Exercises 5 8 (Answers may vary):

A particular random sample had the following information:

̅ = 45 s = 6.5 n= 52 P-value = 0.021 Test Statistic = 2.03

Assuming ̅ & s remain unchanged, identify values of n that would produce the desired result.

5) Identify a value of n that would produce a larger P-value __n=25__(or any n< 52)__

6) Identify a value of n that would produce a larger Test Statistic __ n=100_(or any n> 52)__

7) Now suppose a 95% confidence interval was desired for P __ n=100_(or any n> 52)__

Identify a value of n that would produce a narrower interval.

8) Identify a value of n that would produce more evidence against H0. __ n=100_(or any n> 52)__

9) Migel ed hi on jdgmen hen he aed, Thee i a 30% chance ha he ne Ohio Sae

Uniei Peiden ha Ohio oo. Thi i an eamle of

a) theoretical probability.

b) personal probability.

c) marginal probability.

d) complementary probability.

10) Each student in a class logs the amount of time they spend on Facebook daily for one week. The

students compute their sample averages. Their Teaching Assistant (TA) records the weekly averages

in one column of JMP. The TA also records all of the daily times for all students in another

column. The weekly averages will have a range that is:

a) greater than that of the daily times.

b) the same as that of the daily times (because the data were from the same set of people).

c) the same as that of the daily times (because of the Central Limit Theorem).

d) smaller than that of the daily times.

11) Two events, P(A|B) and P(B), can be best represented by:

a) non-overlapping circles in a Venn Diagram.

b) adjoining branches in a Tree Diagram.

c) the sum of their probabilities.

d) the mean of their probabilities.

12) The anticipated positive impact a vaccine has had on a dozen subjects that were suffering from an

ailmen a meaed b each aien engh. Sengh a meaed befoe-and-after vaccine

administration. The variable: Difference = Strength After Strength Before was created. The

appropriate alternative hypothesis for the population mean difference in patient strength is:

a) Ha: P = 0

b) Ha: P 0

c) Ha: P > 0

d) Ha: P0