The null and alternate hypotheses are:
H0 : μ1 =
μ2
H1 : μ1 ≠
μ2
A random sample of 9 observations from one population revealed a sample mean of 24 and a sample standard deviation of 3.7. A random sample of 6 observations from another population revealed a sample mean of 28 and a sample standard deviation of 4.6.
At the 0.01 significance level, is there a difference between the population means?
a. State the decision rule. (Negative values should be indicated by a minus sign. Round your answers to 3 decimal places.)
b. Compute the pooled estimate of the population variance. (Round your answer to 3 decimal places.)
c. Compute the test statistic. (Negative value should be indicated by a minus sign. Round your answer to 3 decimal places.)
d. State your decision about the null hypothesis.
e.The p-value is
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In: Math
Professor X travels from Houston to Istanbul with stop overs in New York and Londa. At each stop he luggage is transferred from one plane to another. In each airport, including Houston, chances are that with probability p her luggage is not placed in the right plane. Professor X finds that his suitcase has not reached Istanbul. What are the chances that the mishap took place in Houston, New York, and London, respectively?
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Problem 3: A Corporate Perceptions Study surveyed 200 readers and asked them on how they would rate XYZ Corporation on the “Quality of Management” and the “Reputation of the Company”. The two variables of the study were rated on a categorical scale as excellent, good, and fair. The sample data on 200 responses for the study is summarized as follows. Conduct an appropriate hypothesis test for this problem to check if the variables are independent of each other. Reputation of Company Quality of Management Excellent Good Fair Excellent 39 26 5 Good 36 34 10 Fair 25 10 15 Problem 3d) Calculate and show the chi-square components in a table. What is the test statistic value? Problem 3e) Type in the Excel function with inputs to be used to determine p-value. What is the p-value? Conduct Hypothesis test using p-value approach (at .004 level of significance). What is the decision on the hypothesis test? Problem 3f) Type in the Excel function with inputs to be used to determine Critical-value. What is the Critical-value? Conduct Hypothesis test using Critical-Value approach (at .008 level of significance). What is the decision on the hypothesis test? Problem 3g) Are the decisions under the p-value and critical-value approaches different? If they are different, why are they different? If they are not different, why are they not different? Problem 3h) Based on test decisions under parts 3e) and 3f), what conclusion would you draw? Does your conclusion sound meaningful?
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Identify the population, variables, types of variables, type of sampling plan used, and any potential sources of bias in the following situation. Researchers spend one Saturday night waiting outside of a bar to conduct a survey on attitudes towards drinking and driving. They ask every 5th person who comes out of the bar the number of drinks they had that night, their age, and if they believe that drinking and driving is a serious problem.
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In: Math
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A researcher recruited a sample of 5 women who were interested in trying a new six-week program of diet and exercise designed to promote healthy weight loss. She plans to use the .01 significance level to test whether weight decreases (on average) for women using this program. The table below gives the starting and end weights (in pounds) for each of the five women.
Subject | Starting Wt. (Sample 1) | Ending Wt. (Sample 2) |
1 | 174 | 156 |
2 | 122 | 110 |
3 | 169 | 160 |
4 | 181 | 165 |
5 | 147 | 139 |
a. Should these samples be considered paired or independent? Why?
b. Chose the appropriate formula for the test statistic and finds its value.
c. Describe the rejection region for this test.
d. What should the researcher conclude?
e. Find a 95% confidence interval for the mean weight-loss of women using this program. What mean weightless would you predict for women who follow this program?
An independently selected sample of five men also participated in the same study. The table below shows results for the number of pounds lost by the five men and the five women in the study. The researcher will use the .01 significance level to test whether (on average) the program produces different weight loss results for men and women. You may assume the population variances are equal (although the sample variances are not).
Weight Loss (in pounds) | ||
---|---|---|
Men (Sample 1) | Women (Sample 2) | |
Sample Size | 5 | 5 |
Sample mean | 19.2 | 12.6 |
Standard deviation | 4.970 | 4.336 |
f. Formulate the hypothesis for this test.
g. Should the pooled-sample variance be used in this situation? Why?
h. Choose the appropriate formula for the test statistic and find its value.
i. What is the rejection region for this test?
j. What should the researcher conclude?
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In: Math
Propose the key factors in designing a questionnaire.
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Plug-in estimates: Unbiased estimates are not transformation invariant, Show that:
a.) In N(μ, σ2), x̄2 is not an unbiased estimate of μ2
b.) In Exponential(λ), e^(-x̄ ) is not an unbiased estimate of λ.
c.) In Poisson(λ), e^(-x̄ ) is not an unbiased estimate of e^λ.
d.) s is not an unbiased estimate of σ
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Annual revenues are used to predict the value of a baseball franchise. A sample of 32 franchises was used. An analysis of variance of these data showed that b1= 5.0785 and Sb1 = 0.2357.
a. At the 0.05 level of significance, is there evidence of a linear relationship between annual revenue and franchise value?
b. Construct a 95% confidence interval estimate of the population slope, β1.
a: Compute the test statistic. tSTAT= (Round to four decimal places as needed.)
The critical value(s) is(are) (Round to four decimal places as needed.)
b: The 95% confidence interval is ____ ≤ β1 ≤ ____ (Round to four decimal places as needed.)
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A researcher conducts a study of white and black attitudes toward the police in her community.
The percentage of a random sample of white respondents (N = 200) who say they have a favorable attitude toward the police is 53%. The percentage of a random sample of black respondents (N = 200) who say they have a favorable attitude toward the police is 45%.
You are asked if there is a real difference between the percentage of whites and blacks who have a positive attitude toward the police in the larger population, or is this sample difference likely to have occurred by random chance or sampling error.
How do you respond? Explain your answer.
Construct a 95% confidence interval for the proportion of Blacks in the population who have a favorable attitude toward the police
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A gender-selection technique is designed to increase the likelihood that a baby will be a girl. In the results of the gender-selection technique,
861861
births consisted of
443443
baby girls and
418418
baby boys. In analyzing these results, assume that boys and girls are equally likely.
a. Find the probability of getting exactly
443443
girls in
861861
births.
b. Find the probability of getting
443443
or more girls in
861861
births. If boys and girls are equally likely, is
443443
girls in
861861
births unusually high?
c. Which probability is relevant for trying to determine whether the technique is effective: the result from part (a) or the result from part (b)?
d. Based on the results, does it appear that the gender-selection technique is effective?
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In 2014, a group of students was interested in investigating prices of rental accommodation in suburbs of Brisbane that are close to the CBD and collected information on a total of 200 randomly chosen dwellings in four inner western suburbs. A subset of this data, relating to rental apartments in these suburbs is included below. The variables are:
Per week: weekly rental price for the apartment ($);
Bedrooms: number of bedrooms in the apartment;
Sqm: size of the apartment (m2)
Furnished: whether the apartment was furnished or not (yes/no).
The values are;
265,2,59,No
305,2,70,No
300,1,72,No
320,3,66,No
340,2,113,Yes
330,2,58,Yes
355,2,63,No
345,2,57,Yes
355,2,61,No
360,2,114,Yes
355,2,75,Yes
360,2,68,No
365,2,64,No
370,1,69,No
390,2,73,Yes
380,2,85,Yes
390,2,56,Yes
370,2,56,Yes
385,2,59,Yes
380,2,65,Yes
385,2,62,Yes
400,2,65,No
415,2,69,Yes
400,3,63,No
405,3,70,No
420,2,77,No
435,2,84,Yes
435,2,83,Yes
455,2,73,Yes
450,2,72,Yes
485,2,68,No
500,2,76,Yes
535,2,97,No
290,1,60,No
305,1,63,Yes
330,2,65,No
310,2,70,No
335,2,64,No
330,2,62,No
345,2,79,No
355,1,81,No
340,2,66,No
345,1,60,No
345,2,64,No
355,2,73,No
385,2,61,No
380,2,78,No
405,2,81,No
410,2,76,Yes
430,2,80,No
440,2,61,No
450,3,86,No
485,3,91,No
500,1,87,No
545,1,97,Yes
345,3,86,No
400,2,72,No
400,2,74,No
480,2,73,Yes
755,3,87,No
760,3,77,No
770,3,113,No
824,2,109,No
860,3,104,No
295,1,70,No
290,1,54,No
295,1,61,No
325,1,61,No
340,2,56,No
355,2,61,No
365,2,95,No
420,1,75,No
420,2,66,No
440,2,74,No
480,3,72,No
465,3,87,No
470,1,87,Yes
490,1,81,Yes
495,2,76,No
505,2,97,No
530,2,77,No
545,2,97,No
560,2,79,No
550,2,78,No
560,3,75,No
565,1,96,Yes
580,2,85,Yes
605,3,84,No
605,2,93,Yes
610,2,78,Yes
620,2,87,No
665,2,88,No
700,2,80,No
750,3,97,Yes
740,3,124,No
805,3,101,No
860,3,98,No
960,3,123,Yes
990,3,102,Yes
1195,3,133,No
1190,3,137,No
1405,3,148,Yes
1490,3,154,No
Q1)
The students were interested in exploring the relationship between apartment size and weekly rent. Using R, fit a linear regression relating weekly rent to apartment size; that is, a model of the form:
per. week = β0 + β1 sqm + ε,
and answer the following questions:
(a) What is the MSE (mean-squared error) for this regression? What are the degrees of freedom associated with this value?
(b) Find a 95% confidence interval for the intercept parameter in this model. You may take relevant statistics from the R output for your regression, but please show full working.
(c) Another group of students suggest that apartment pricing is known to increase with apartment size at an average rate of $12 per square metre. Carry out a formal test of this hypothesis and interpret the resulting p-value, using α = 0.05.
(d) You intend to use your research to help inform fair weekly rent for a friend, who is looking at renting an apartment of size 60 m2 . Using R, find a 95% prediction interval for the weekly rent of this apartment.
(e) Construct a residual and normal quantile plot for this analysis. Are there any issues with the underlying assumptions of linearity and/or homoscedasticity?
Please answer this question by using R code !!!!!!! it is very important
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