The variable of interest in an investigation is the score obtained by two populations of final-year students from a mathematics achievement test.The researchers assume that the scores of the two populations were normally distributed with means μ1=50, μ2=40 and variances σ21=25, σ22=49 a random sample of 10 students. selects from the first population and another independently the fi

The variable of interest in an investigation is the score obtained by two populations of final-year students from a mathematics achievement test.The researchers assume that the scores of the two populations were normally distributed with means μ1=50, μ2=40 and variances σ21=25, σ22=49 a random sample of 10 students. selects from the first population and another independently the fi

A First Course in Probability (10th Edition)

10th Edition

ISBN:9780134753119

Author:Sheldon Ross

Publisher:Sheldon Ross

Chapter1: Combinatorial Analysis

Section: Chapter Questions

Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...

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One sample has n=7 and SS=35 and a second sample has n =17 and SS =45. What is the pooled variance for these two samples?
Two samples. each with n = 5 scores, have a pooled variance of 40. What is the estimated standard error for the sample mean uniference? how do i solve?
A behavioral researcher measures the stress response of mice exposed to scary animal pictures (cat, dog, lion, Cheshire cat) with a GABA sensor implanted in the brain. He uses randomly assigned 40 mice, 10 in each group. The researcher records the amount of stress after 30 seconds assuming that there is no difference in the response in whatever way the mouse is scared. The data is normally distributed. Means and variances are provided in the table below. Is there a difference in the response to scary animals. Group 1 - Cat n₁=10 m₁ = 10 s² 1= 1.8 Group 2 - Dog n2=10 m₂= 5.0 s²2= 3.4 Why is the scare effect so low in group 4? Group 3 - Lion n3=10 m3= 3.4 s²1= 2.5 Group 4 - Chesire Cat n4=10 m4= 2.4 s² 1= 1.6
We are running a hypothesis test to see if blood pressure of African zebras differs significantly from Arabian horses. We assume blood pressure in both populations is normally distributed and both populations have the same population variance in blood pressure which is unknown to us, so we use the sample variances to estimate the standard error for our calculations. We have a sample of size 9 for the African zebras and a sample of size 16 for the Arabian horses. How many degrees of freedom does our test statistic have?
Thompson and Thompson is a steel bolts manufacturing company. Their current steel bolts have a mean diameter of 126126 millimeters, and a variance of 6464. If a random sample of 3939 steel bolts is selected, what is the probability that the sample mean would differ from the population mean by greater than 3.33.3 millimeters? Round your answer to four decimal places.
The data from an independent-measures research study produce a sample mean difference of 4 points, and each sample has a variance of 10. If there are n = 20 scores in each sample, then what is the estimated standard error of the difference between means?
If a population forms a normal shaped distribution with µ =40 and σ = 8 and a sample of 16 scores from this population has a mean of 36, would this sample be relatively typical or extreme?
We are running a hypothesis test to see if weight of African zebras is significantly different than that of Arabian horses. We assume weight in both populations is normally distributed and both populations have the same population variance in weight which is unknown to us, so we use the sample variances to estimate the standard error for our calculations. We have a sample of size 9 for the African zebras with mean 650 and a sample of size 16 for the Arabian horses with mean 659. If the pooled variance is 81, then what is the absolute value of the standardized test statistic for our data?
A sample with SS=30 and a variance of s2 =10 has n=4 scores. True or False?
Suppose a researcher pbserves a population of 12 people and computes SS=204. What is the variance? What is the standard deviation?