Many psychologists are concerned that the average level of anxiety in children has increased over the past 40 years. In the 1980s, the population average score on the ChildManifest Anxiety Scale (CMAS) was 15.1. In 2021, a random sample of 101 children was tested with CMAS. The mean for the sample was 16.1 with the standard deviation of4. Is there enough evidence to claim that there has been a significant change in the average level of anxiety since the 1980s? Conduct the appropriate statistical test (two-tailed) with a = .05.Which of the following are critical values for the analysis?O 1.984|11.990|11.962||1.660|

That is, there is no evidence to conclude that there is significant change in the average level of…

Answered: Many psychologists are concerned that…

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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Solar energy is considered by many to be the energy of the future. A recent survey was taken to compare the cost of solar energy to the cost of gas or electric energy. Results of the survey revealed that the distribution of the amount of the monthly utility bill of a three-bedroom house using gas or electric energy had a mean of $117 and a standard deviation of $13. If the distribution can be considered normal: Approximately what percentage of homes will have a monthly utility bill less than $78? Note: Do NOT include the "%" sign Do NOT round any decimals, if applicable
On the PSAT test taken by about 1.5 million high school juniors each year, the mean score on the reading portion of the test was 46.9, with a standard deviation of 10.9. The scores are normally distributed. If a student needed a score on this portion of the test that put them in the top 5% of scores nationally to qualify for a particular scholarship, what is the minimum score they must achieve?
The college physical education department offered an advanced first aid course last summer. The scores on the comprehensive final exam were normally distributed, and the z-scores for some of the students are shown below. Robert 1.05 Juan 1.51 Haley −1.95 Joel 0.00 Jan −0.67 Linda 1.57 (a) If the mean score was ? = 151 with standard deviation ? = 16, what was the final exam score for each student?
John finds that there is a scholarship available to all persons scoring in the top 5 % on the ACT test. If the mean score on the ACT is 21 with a standard deviation of 4.7, what score does he need in order to qualify for the scholarship?
Suppose the value of a stock varies each day from $10.82 to $23.17 with a uniform distribution. Find the third quartile, i.e. , 75% of all days the stock is below what value ?
Dr. Jill Biden has been teaching a seventh grade English composition class for many years. She has the feeling that over the past several years, the writing ability of students has changed. A national test of proficiency in composition was administered 5 years ago. The resulting distribution of scores was normally shaped, had a mean of 85 and a standard deviation of 10.9. In order to test his feeling, she gives her present class of 43 students the same proficiency test. The resulting mean is 80 and the standard deviation is 8.7. a. What is the alternative hypothesis? b. What is the null hypothesis? c. What is your conclusion, using an alpha of 0.05 (2 tailed). d. What type of error might you be making because of your conclusion in part c?
Suppose there is a city where the mean cost per month of a one-bedroom apartment is $1,500, with a standard deviation of $250. Approximately what percentage of one-bedroom apartments in the city cost between $750 and $1,000?
A successful basketball player has a height of 6 feet 11 inches, or 211 cm. Based on statistics from a data set, his height converts to the z score of 5.17. How many standard deviations is his height above the mean?
In the class of 2019, more than 1.6 million students took the SAT. The distribution of scores on the math section (out of 800) is approximately normal with a mean of 528 and standard deviation of 117. What proportion of students earned scores between 500 and 600 on the SAT math test?
Suppose we know that the aspirin content of aspirin tablets follows a Normal distribution with standard deviation of o= 5 mg.
... ... ... ..
According to Chebyshev's Rule, at least what percent of observations must be within 2.5 standard deviations from the mean? [a]%

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