A researcher wanted to know if a student’s book series preference was dependent
ID: 3049911 • Letter: A
Question
A researcher wanted to know if a student’s book series preference was dependent upon the year they were in school. They collected data from 1000 students and asked them if the preferred the Harry Potter series, the Hunger games series, or the A Song of Ice and Fire series and what year they were in school. The results from the survey are below:
Book Preference
Year Harry Potter Hunger Games A Song of Ice and Fire Total
Freshman 125 ( ) 50 ( ) 75 ( ) 250
Sophomore 90 ( ) 120 ( ) 40 ( ) 250
Junior 60 ( ) 175 ( ) 15 ( ) 250
Senior 25 ( ) 75 ( ) 150 ( ) 250
Total 300 420 280 1000
In a separate word file, answer the following questions using complete sentences when applicable and copying and pasting the relevant charts, tables and graphs when appropriate.
1. Identify the population, the sample, and the variables from this study.
2. Identify the independent and the dependent variables from this study and why you identified them that way.
3. In the space below, calculate the expected values for each cell in the contingency table and write those values in the parentheses in the data table above (show all of you work).
4. Using = 0.05, perform a chi-square test to answer the researcher’s question. Write up your conclusion.
Explanation / Answer
A researcher wanted to know if a student’s book series preference was
dependent upon the year they were in school
a.
total no.of students they were in school is the population and the study of 1000 students
who randomly picked is the sample
b.
book series preference is the dependent variable and year of study is the
indepdndent variable
c.
Given table data is as below
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calculation formula for E table matrix
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expected frequecies calculated by applying E - table matrix formulae
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calculate chisquare test statistic using given observed frequencies, calculated expected frequencies from above
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set up null vs alternative as
null, Ho: book series preference is independent on year of study
alternative, H1: book series preference is dependent on year of study
level of significance, = 0.05
from standard normal table, chi square value at right tailed, ^2 /2 =12.592
since our test is right tailed,reject Ho when ^2 o > 12.592
we use test statistic ^2 o = (Oi-Ei)^2/Ei
from the table , ^2 o = 306.714
critical value
the value of |^2 | at los 0.05 with d.f (r-1)(c-1)= ( 4 -1 ) * ( 3 - 1 ) = 3 * 2 = 6 is 12.592
we got | ^2| =306.714 & | ^2 | =12.592
make decision
hence value of | ^2 o | > | ^2 | and here we reject Ho
^2 p_value =0
ANSWERS
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null, Ho: book series preference is independent on year of study
alternative, H1: book series preference is dependent on year of study
test statistic: 306.714
critical value: 12.592
p-value:0
decision: reject Ho
have evidence thtat book series preference is dependent on year of study
MATRIX col1 col2 col3 TOTALS row 1 125 50 75 250 row 2 90 120 40 250 row 3 60 175 15 250 row 4 25 75 150 250 TOTALS 300 420 280 1000Related Questions
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