In an educational study, there is interest in whether or not there is more variability in the mean verbal scores of 8-year-olds or of 3-year-ol

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In an educational study, there is interest in whether or not there is more variability in the mean verbal scores of 8-year-olds or of 3-year-olds. Summary statistics are given below.

  Sample Size Mean St. Dev.
Age 8 60 93.5 5.4
Age 3 60 78.6 2.7

To test H0: σ8 = σ versues Ha: σ> σ3, the resaerchers will use the ratio of the sample satnadard deviations, s8/s3, as a test statistic. 

a.) What is the observed test statistic from the data of this study?

b.) A simulation was conducted to study the sampling distribution of this test statistic. For each repetition of the simulation, two random samples were generated using appropriate population means with identical standard deviations, and the ratio of the sample standard deviations was noted. A histogram of the simulated ratios is given below. 

 

(see attachement, histgram skewed to the right with values ranging from 0.5 to 2.0.

 

Is there statistically significant evidence that there is more variability in the mean verbal scores of 8-year-olds than of 3-year-olds?

*600. In an educational study, there is interest in whether or not there is more
variability in the mean verbal scores of 8-year-olds or of 3-year-olds.
Summary statistics are given below.
Sample Size
Мean
StDev
Age 8
60
93.5
5.4
Age 3
60
78.6
2.7
To test Ho: og = 03 versus H: 0g > Oz, the researchers will use the ratio of the
sample standard deviations, s 8 s 3 , as a test statistic.
%3!
(a) What is the observed test statistic from the data of this study?
(b) A simulation was conducted to study the sampling distribution of this
test statistic. For each repetition of the simulation, two random samples
were generated using appropriate population means with identical
standard deviations, and the ratio of the sample standard deviations
was noted. A histogram of the simulated ratios is given below.
05
Simulated ratios of sample standard deviations
1.0
1.5
2.0
Is there statistically significant evidence that there is more variability in
the mean verbal scores of 8-year-olds than of 3-year-olds?
Transcribed Image Text:*600. In an educational study, there is interest in whether or not there is more variability in the mean verbal scores of 8-year-olds or of 3-year-olds. Summary statistics are given below. Sample Size Мean StDev Age 8 60 93.5 5.4 Age 3 60 78.6 2.7 To test Ho: og = 03 versus H: 0g > Oz, the researchers will use the ratio of the sample standard deviations, s 8 s 3 , as a test statistic. %3! (a) What is the observed test statistic from the data of this study? (b) A simulation was conducted to study the sampling distribution of this test statistic. For each repetition of the simulation, two random samples were generated using appropriate population means with identical standard deviations, and the ratio of the sample standard deviations was noted. A histogram of the simulated ratios is given below. 05 Simulated ratios of sample standard deviations 1.0 1.5 2.0 Is there statistically significant evidence that there is more variability in the mean verbal scores of 8-year-olds than of 3-year-olds?
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