A certain counselor wishes to compare the mean IQ scores of two different social groups. A random sample of 12group IQ scores1showed an average of85and astandard deviation offiftewhile a random sample chosen independently ofelegroup IQ scores2showed an average of 108and a standard deviation of13. Assumingthat the populations of IQ scores for each of the groups follow a normal distribution and that the variances of these populations are equal, construct aconfidence interval for the90%forμ₁ −μ₂, the difference between the meanµ₁group IQ scoresland the meanμgroup IQ scores2. Then find the lower limit andthe upper limit of the confidence interval of the90%.-Carry out intermediate calculations using at least three decimal places. Round answers to at least two decimal places. (If necessary, you can refer to a list offormulas.)Lower limit:Upper limit:XŚ

Given that for group 1: mean (M1) = 85, standard deviation (s1) = 15 and n1 = 12group 2: mean (M2) =…

Answered: A certain counselor wishes to compare…

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

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Given that the researcher wants to be sure the mean difference in the change in hemoglobin levels has a margin of error no more than 0.2 g/dL and the difference in the stand deviation between the mean hemoglobin levels for the two forms of iron supplements used to treat anemia is 1.2 g/dL, what is the desired number of recruits for the study, assuming the individuals will participate in a crossover trial, if the study’s attrition rate is expected to be .25? Group of answer choices n = 139 n = 554 n = 185 n = 55,320
A number of 28 university students who smokes completed a questionnaire inquiring their smoking history and behavior. The result shows that the average smoking initiation age of this group is 21.6 years with a variance of 18.49. Based on past record, the smoking initiation age of university student has a mean of 20.74 years with a standard deviation of 5.1 years. Conduct a necessary analysis to determine if the smoking initiation age remain the same as the previous record. Use 4% level of significance.
Paint used to paint lines on roads must reflect enough light to be clearly visible at night. Researchers have 2 new types of paints they want to test paint type A and paint type B. For each paint type, they tested if there was statistical evidence the average reflectometer reading is greater than 35. To test each type of paint, they used 15 paint samples. Further, suppose the standard deviation is the same for both types of paints. The sample mean for paint type A was 39 and the sample mean for paint type B was 41.5. For both statistical tests, the significance level is set to .05.Which of the following is true? If they fail to reject the null hypothesis for paint type A we can conclude there is statistical evidence the average reflectometer for type A paint is 35. The p-value for the type B paint test is smaller. They rejected the null hypothesis for both paint types. Exactly two of the statements above are true. None are true.
A researcher wants to compare the effectiveness of two different study techniques for a test. The mean test score for the first technique is 75 with a standard deviation of 5, and the mean test score for the second technique is 80 with a standard deviation of 4. The sample size for each group is 20. What is the 95% Confidence Interval for the difference in the mean test scores for the two techniques?
A psychology graduate student wants to test the claim that there is a significant difference between the IQs of spouses. To test this claim, she measures the IQs of 9 married couples using a standard IQ test. The results of the IQ tests are listed in the following table. Using a 0.10 level of significance, test the claim that there is a significant difference between the IQs assuming that the population distribution of the paired differences is approximately normal. Let the spouse 1 group be Population 1 and let the spouse 2 group be Population 2. Spouse 1 Spouse 2 IQs of Married Couples 124 113 97 123 121 101 128 116 96 126 119 100 Copy Data Step 2 of 3: Compute the value of the test statistic. Round your answer to three decimal places. 124 111 127 113 107 111
Assume a researcher wants to compare the mean Alanine Aminotransferase (ALT) levels in two populations, individuals who drink alcohol and individuals who do not drink alcohol. The mean ALT levels for the individuals who do not drink alcohol is 32 with a standard deviation of 14, and 37 individuals were in the sample. The mean ALT levels for individuals who drink alcohol is 69 with a standard deviation of 19, and 38 individuals were in the sample. Construct and interpret a 95% confidence interval demonstrating the difference in means for those individuals who drink alcohol when compared to those who do not drink alcohol.
Medical researchers are interested in determining the relative effectiveness of two drug treatments on patients with a chronic mental illness. Treatment 1 has been around for many years, while treatment 2 has recently been developed based on the latest research. The researchers chose two independent test groups. The first group had 9 patients, all of whom received treatment and had a mean time until remission of 166 days, with a standard deviation of 8 days. The second group had 15 patients, all of whom received treatment 2 and had a mean time until remission of 161 days, with a standard deviation of 9 days. Assume that the populations of times until remission for each of the two treatments are normally distributed with equal variance. Can we conclude, at the 0.05 level of significance, that u, the mean number of days until remission after treatment 1, is greater than u,, the mean number of days until remission after treatment 2? Perform a one-tailed test. Then complete the parts…
Listed in the data table are IQ scores for a random sample of subjects with medium lead levels in their blood. Also listed are statistics from a study done of IQ scores for a random sample of subjects with high lead levels. Assume that the two samples are independent simple random samples selected from normally distributed populations. Do not assume that the population standard deviations are equal Use a 0.05 significance level to test the claim that the mean IQ scores for subjects with medium lead levels is higher than the mean for subjects with high lead levels. 1. What is the test statistic and P-Value? 2. State the conclusion for the test. 3. Construct a confidence interval suitable for testing the claim that students taking nonproctored tests get a higher mean score than those taking proctored tests. ____ < μ1 - μ2 < ____
Given that the researcher wants to be sure the mean difference in the change in hemoglobin levels has a margin of error no more than 0.2 g/dL and the difference in the stand deviation between the mean hemoglobin levels for the two forms of iron supplements used to treat anemia is 1.2 g/dL, what is the desired number of recruits for the study, assuming the individuals will participate in a crossover trial, if the study’s attrition rate is expected to be .25? Group of answer choices n= 139 n= 186 n= 554 n= 55,320
Researchers from a certain country were interested in how characteristics of the spleen of residents in their tropical environment compare to those found elsewhere in the world. The researchers randomly sampled 91 males and 109 females in their country. The mean and standard deviation of the spleen lengths for the males were 10.9 cm and 0.9 cm, respectively, and those for the females were 9.8 cm and 1.1 cm, respectively. Determine a 95% confidence interval for the difference between mean spleen lengths of males and females in this country. Click here to view page 1 of the table of critical values of t. Click here to view page 2 of the table of critical values of t. Let population 1 be all males in the country and let population 2 be all females in the country. The 95% confidence interval for µ1 - 4½ is ( | D (Round to three decimal places as needed. Use ascending order.)

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