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Short Answer

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The proportion of explained variability (SSR) among overall variability is calculated using the sum of squares of total (SST), sum of squares due to regression (SSR), sum of squares of errors (SSE), and R-square (SST)

Step by step solution

01

Introduction.

Simple random sampling (SRS) is a method for selecting a sample of n number of sampling units from a population of N number of sampling units.

02

Given Information (part a).

We present data from separate simple random samples drawn from multiple populations; compute SST, SSTR, and SSE using the computational formulas in each case.

03

  Step 3: Explanation (part a).

04

Given Information (part b).

We give data from different simple random samples selected from multiple populations, and then compute SST, SSTR, and SSE using the appropriate computational methods.

05

  Step 5: Explanation (part b).

We have


k=3,n_1=2,n_2=5,n_3=3,T_1=10,T_2=30,andT_3=30n=sumn_j=2+5+3=10sumx_i=sumT_j=10+30+30=70

Summing the squares of all the data in the above table yields


xi2=(1)2+(9)2+(10)2+.+(16)2+(10)2=674

06

Given Information (part c).

We provide data from several basic random samples drawn from multiple populations, and then use the proper computational methods to compute SST, SSTR, and SSE.

07

  Step 7: Explanation (part c).

Consequently,

SST=(sumxi)2-(sumxi)2/n=674-(70)2/10=674-490=184SSTR=sum(Tj2)/n-(sumxj)2/n=(10)2/2+(30)2/5+(30)2/3-(70)2/10=530-490=40SSE=SST-SSTR=184-40=144

08

Given Information (part d).

We offer data from numerous basic random samples selected from diverse populations, and then compute SST, SSTR, and SSE using the appropriate computational methods.

09

  Step 9: Explanation (part d).

Both the results are the same. Even though we use a different version of computations both yield the same results.

10

Given Information (part e).

We provide data from a variety of basic random samples drawn from various demographics, and then use the proper computational methods to compute SST, SSTR, and SSE.

11

  Step 11: Explanation (part e).

Thus treatment mean square is

MSTR=SSTR/k-1=40/3-1=20

The error mean square is

MSE=SSE/n-k=144/10-3=20.57

The value of F-statistic is

F=MSTR/MSE=20/2.57=0.97

12

Given Information (part f).

We supply data from a range of basic random samples selected from diverse demographics, and then compute SST, SSTR, and SSE using the appropriate computational methods.

13

  Step 13: Explanation (part f).

14

Given Information (part g).

We provide data from a variety of basic random samples drawn from various demographics, and then use the proper computational methods to compute SST, SSTR, and SSE.

15

  Step 15: Explanation (part g).

The null and alternative hypotheses are

H0:μ1=μ2=μ3

H1: Not all the means are equal

We are to perform the test at the 5%significance level; so α=0.05

We have 3 populations under consideration, or k=3, and that the number of observations total 10 , or n=10.

Hence the degrees of freedom for the F-statistic is

df=(k-1,n-k)=(3-1,10-3)=(2,7)

From table VIII, the critical value at the 5%level of significance is F0.05=4.74

Referring to table Vill withdf=(2,7), we find P>0.10

Because the P-value is greater than the significance level we do not reject H0

The data do not provide sufficient evidence to conclude that the means of the populations from which the samples were drawn are not all the same.

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Most popular questions from this chapter

Permeation Sampling. Permeation sampling is a method o sampling air in buildings for pollutants. It can be used over a long period of time and is not affected by humidity, air currents, or temperature. In the paper "Calibration of Permeation Passive Samplers With Silicone Membranes Based on Physicochemical Properties of the Analytes" (Analytical Chemistry, Vol. 75, No, 13, pp. 3182-3192). B. Zabiegata et al. obtained calibration constants experimentally for samples of compounds in each of four compound groups. The following data summarize their results.

At the 5%significance level, do the data provide sufficient evidence to conclude that a difference exists in the mean calibration constant among the four compound groups? (Note:,T3=0.870,T4=0.499,Σxi2=0.456919)

Doing Time. The Federal Bureau of Prisons publishes data in Statistical Report on the times served by prisoners released from federal institutions for the first time. Independent simple random samples of released prisoners for five different offence categories yielded the data on time served, in months, shown on the WeissStats site.

a. Obtain individual normal probability plots and the standard deviation of the samples.

b. Perform a residual analysis.

c. Use your results from parts (a) and (b) to decide whether conducting a one-way ANOVA test on the data is reasonable. If so. also do parts (d) and (e).

d. Use a one-way ANOVA test to decide, at the 5%significance level, Whether the data provide sufficient evidence to conclude that a difference exists among the means of the populations fewer than the samples were taken.

e. Interpret your results from part (d).

An F-curve has df=(24,30). In each case, find the F-value having the specified area to its right.

a.0.05

b.0.01

c.0.025

How many degrees of freedom does an F-curve have? What are those degrees of freedom called?

Breast Milk and IQ. Considerable controversy exists over whether long-term neurodevelopment is affected by nutritional factors in early life. A. Lucas and R. Morley summarized their findings on that question for preterm babies in the publication "Breast Milk and Subsequent Intelligence Quotient in Children Born Preterm (The Lancet, Vol. 339, Issue 8788, Pp, 261-264). The researchers analyzed IQ data on children at age 712-8years. The mothers of the children in the study had chosen whether to provide their infants with breast milk within 72hours of delivery. The researchers used the following designations. Group I: mothers declined to provide breast milk; Group ll a: mothers had chosen but were unable to provide breast milk and Group Il b; mothers had chosen and were able to provide breast milk. Here are the summary statistics on IQ.

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