
Suppose the mass of college students can be modeled by the normal distribution. We believe the mean of the normal distribution is 72 kg. We randomly sample 18 students and find an average of 69 kg and a standard deviation of 4kg. A. The standard error of óx is 0.9428 B. A t...

8A bakery stated that the average number of breads sold daily is 3000. An employee thinks that the actual value might differ from this and wants to test this statement. The correct hypotheses are: (1) H0 : ¦Ì = 3000 H1 : ¦Ì not= 3000 (2) H0 : ¦Ì > 3000 H1...

(a) The test had six multiplechoice items that were scored as correct or incorrect, so the total score was an integer between 0 and 6. Do you think that these data are Normally distributed? Explain why or why not. The distribution is Normal because the standard deviation is ...

(a) The test had six multiplechoice items that were scored as correct or incorrect, so the total score was an integer between 0 and 6. Do you think that these data are Normally distributed? Explain why or why not. The distribution is Normal because the standard deviation is ...

A worker for the American Red Cross wants to predict the average number of blood donations of college students. He takes a random sample of 900 students. But then he is puzzled and asks you: " In my sample most of the students have zero donations and the percentages go down as...


The composite scores of students on the ACT college entrance examination in a recent year had a Normal distribution with mean µ = 20.4 and standard deviation = 5.8. 1) What is the probability that a randomly chosen student scored 24 or higher on the ACT? 2) What are the mean ...

The composite scores of students on the ACT college entrance examination in a recent year had a Normal distribution with mean µ = 20.4 and standard deviation = 5.8. 1) What is the probability that a randomly chosen student scored 24 or higher on the ACT? 2) What are the mean ...

Thirty randomly selected students took the calculus final. If the sample mean was 89 and the standard deviation was 6.2, construct a 99% confidence interval of the mean score of all students. Assume that the population has a normal distribution

The composite scores of students on the ACT college entrance examination in a recent year had a Normal distribution with mean µ = 20.4 and standard deviation = 5.8. 1) What is the probability that a randomly chosen student scored 24 or higher on the ACT? 2) What are the mean ...

Thirty randomly selected students took the calculus final. If the sample mean was 89 and the standard deviation was 6.2, construct a 99% confidence interval of the mean score of all students. Assume that the population has a normal distribution. what formula do i use????

1. Which of the following statements are correct? a. A normal distribution is any distribution that is not unusual. b. The graph of a normal distribution is bellshaped. c. If a population has a normal distribution, the mean and the median are not equal. d. The graph of a ...

Which of the following statements are correct? a. a normal distribution is any distribution that is not unusual b. the graph of a normal distribution is bellshaped c. if a population has a normal distribution, the mean and the median are not equal d. the graph of a normal ...

Which of the following statements are correct? 1.A normal distribution is any distribution that is not unusual. 2.The graph of a normal distribution is bellshaped. 3.If a population has a normal distribution, the mean and the median are not equal. 4.The graph of a normal ...

1. Which of the following statements are correct? a. A normal distribution is any distribution that is not unusual. b. The graph of a normal distribution is bellshaped. c. If a population has a normal distribution, the mean and the median are not equal. d. The graph of a ...

The Survey of Study Habits and Attitudes (SSHA) is a psychological test that measures students' study habits and attitudes toward school. Scores range from 0 to 200. The mean score for college students is about 115.8, and the standard deviation is about 32.9. A teacher ...


The Survey of Study Habits and Attitudes (SSHA) is a psychological test that measures students' study habits and attitudes toward school. Scores range from 0 to 200. The mean score for college students is about 115.8, and the standard deviation is about 32.9. A teacher ...

In a school, the IQ scores of the students have a normal distribution with a mean value of 100, and a standard deviation of 10. What is the probability that the IQ score of a randomly selected student is at least 120? (10 p)

Which of the following statements are correct? a. A normal distribution is any distribution that is not unusual. b. The graph of a normal distribution is bellshaped. c. If a population has normal ditribution, the mean and the median are not equal. d. The graph of a normal ...

which of the following statements are correct? a. a normal distribuiton is any distribution that is not unusual. b. the graph of a normal distribution is bellshaped. c. if a population has a normal distribution, the mean and the median are not equal. d. the graph of a normal ...

A. The GPAs of all 5540 students enrolled at a University have an approximately normal distribution with a mean of 3.02 and a standard deviation of 0.29. Let x be the mean GPA of a random sample of 48 students selected from this University. Find the mean and standard deviation...

The mean GPA (grade point averagE. of all male students at a college is 2.77 and the mean GPA of all female students at the same college is 2.89. Suppose we take one sample of 40 male students and another sample of 50 female students from this college. What is the mean of the ...

Suppose that, for a certain exam, a teacher grades on a curve. It is known that the grades follow a normal distribution with a mean of 70 and a standard deviation of 7. There are 45 students in the class. How many students should receive an A? Please, round your answer to the ...

A) Choose one of the following distributions (positively skewed normal distribution, negatively skewed normal distribution or bimodal normal distribution) and generate a sample of 20 numbers for it. The sample you generate should have a mean of 8 and a sample standard ...

The GPAs of all students enrolled at a large university have an approximately normal distribution with a mean of 3.02 and a standard deviation of .29. Find the probability that the mean GPA of a random sample of 20 students selected from this university is 2.87 or lower

The Office of Student Services at a large western state university maintains information on the study habits of its fulltime students. Their studies indicate that the mean amount of time undergraduate students study per week is 20 hours. The hours studied follows the normal ...


Find an example of application of Normal Distribution (or approximately Normal Distribution) in your workplace or business (or any other business that you are familiar with). Prove that the variable has the characteristics of a Normal Distribution. Recall that the variable ...

2.5 Points 30% of the fifth grade students in a large school district read below grade level. The distribution of sample proportions of samples of 100 students from this population is normal with a mean of 0.30 and a standard deviation of 0.045. Suppose that you select a ...

1)Suppose that the weight of tomato juice in mechanically filled cans follows a normal distribution with a mean of 464 grams and a standard deviation of 8 grams. a)A random sample of size n = 18 cans is taken. Will the sampling distribution of the sample mean weight be normal...

Suppose that the probability distribution of a random variable x can be described by the formula P(x) = x/15 For each of the values x = 1, 2, 3, 4, and 5. For examples, then, p(x=2) = p(2) = 2/15 a Write out the probability distribution of x. b Show that the probability ...

Head lice can be a problem in classrooms. From the past experience, suppose it is predicted that 5% of the students will get lice if there are some reported cases. The health nurse checks 120 randomly chosen students and records the number of students that have head lice. What...

30% of the fifth grade students in a large school district read below grade level. The distribution of sample proportions of samples of 100 students from this population is normal with a mean of 0.30 and a standard deviation of 0.045. Suppose that you select a sample of 100 ...

30% of the fifth grade students in a large school district read below grade level. The distribution of sample proportions of samples of 100 students from this population is normal with a mean of 0.30 and a standard deviation of 0.045. Suppose that you select a sample of 100 ...

The business college computing center wants to determine the proportion of business students who have laptop computers. If the proportion exceeds 35%, then the lab will scale back a proposed enlargement of its facilities. Suppose 200 business students were randomly sampled and...

Suppose X has a moundshaped distribution with sigma=9. A random sample of size 36 has a sample mean 20. Is it appropriate to use a normal distribution to compute a confidence interval for the population mean u?

Suppose that the ages of students at a particular university average 26 years with a standard deviation of 2.8 years. Consider the sampling distribution of the sample mean age of students in a sample of n = 49. The mean of the sampling distribution is __________


To estimate the mean height population of male students on your campus, you will measure and SRS of students. Heights of people the same sex and similiar ages are close to normal. You know from government data that the standard deviation of the heights of young men is about 2....

The scores of students on the ACT college entrance examination in a recent year had a normal distribution with a mean of 18.6 and a standard deviation of 5.9. A simple random sample of 50 students who took the exam is selected for study: A) What is the shape, mean, and ...

1. Which of the following statements are correct? a. A normal distribution is any distribution that is not unusual. (True/False) b. The graph of a normal distribution is bellshaped. (True/False) c. If a population has a normal distribution, the mean and the median are not ...

Over 350 students took a college calculus final exam. the scores of the students follow a normal distribution. using the information given below, determine the mean and the standard deviation for the students'scores. Give your answers to the nearest tenth of a percent. 1. 32% ...

Decide which of the variables described is likely to have a normal or nearnormal distribution. a. The number of courses remaining until graduation for the students in a small liberal arts college b. The SAT mathematics scores for students in an advanced placement mathematics ...

Which of the following normal distributions has the smallest spread? A. A normal distribution with mean 1 and standard deviation 3 B. A normal distribution with mean 0 and standard deviation 2 C. A normal distribution with mean 3 and standard deviation 2 D. A normal ...

Considered the sampling distribution of a sample mean obtained by random sampling from an infinite population. This population has a distribution that is highly skewed toward the larger values. a) How is the mean of the sampling distribution related to the mean of the ...

1. The scores of students on the ACT college entrance examination in a recent year had a normal distribution with a mean of 18.6 and a standard deviation of 5.9. A simple random sample of 60 students who took the exam is selected for study: a) What is the shape, mean(expected ...

When making a decision on whether a sample mean is significantly different than a population mean given that you sampled a small sample (n), what is the correct reasoning for choosing the tdistribution over the standard normal distribution (zdistribution)?

Suppose that the probability distribution of a random variable x can be described by the formula P(x) = x/15 For each of the values x = 1, 2, 3, 4, and 5. For examples, then, p(x=2) = p(2) = 2/15 a Write out the probability distribution of x. b Show that the probability ...


Decide which of the variables described is likely to have a normal or nearnormal distribution. a. The number of courses remaining until graduation for the students in a small liberal arts college b. The SAT mathematics scores for students in an advanced placement mathematics ...

Decide which variables described is likely to have a normal or near normal distribution a. the number of courses remaining until graduation for the students in a small liveral arts college b. the SAT math scores for students in an advanced placement math class i think the ...

You are interested in estimating the mean of a population. you plan to take a random sample from the population and use the samples mean as an estimate of population mean. Assuming that the population from which you select your sample is normal, which of the statements about ...

A sample of 106 students, the researchers reported the following statistics...mean= 13.2 s=19.5 Explain why the distribution for these 106 students cannot be symmetric and given this, what % of 106 students fall within the x+/2s? I understand it cannot be symmetric b/c the ...

As the degrees of freedom for the tdistribution increase, the distribution approaches the value of zero for the mean. the tdistribution. the normal distribution. the F distribution. I'm thinking C...

I am not sure how to even get started on this question could someone help please. A college advisor wants to estimate the mean annual income of all college students who graduated last year. It is believed that the incomes follow a normal distribution with population standard ...

As the degrees of freedom for the tdistribution increase, the distribution approaches the value of zero for the mean. the tdistribution. the normal distribution. the F distribution.

The standard deviation of GPAs (grade point averages) of all male students at a college is .35 and the standard deviation of GPAs of all female students at the same college is .34. Suppose we take one sample of 40 male students and another sample of 50 female students from ...

A class survey in a large class for firstyear college students asked, "About how many minutes do you study on a typical weeknight?" The mean response of the 463 students was x = 118 minutes. Suppose that we know that the study time follows a Normal distribution with standard ...

a test has a mean score 73 with standard deviation of 12.students with scores greater than 85 receive an A. What is the percent of the students would we expect to get an A? assume the normal distribution


1.)Suppose you interview 10 randomly selected workers and ask how many miles they commute to work. You'll compute the sample mean commute distance. Now imagine repeating the survey many, many times, each time recording a different sample mean commute distance. In the long run...

the length of times it takes college students to find a parking spot im the library parking lot follows a normal distribution with a mean of 5.5 minutes and a standard deviation of 1 minute. find the cut off time which 75.8% of the college students exceed when trying to find a...

The length of time it takes college students to find a parking spot in the library parking lot follows a normal distribution with a mean of 4.0 minutes and a standard deviation of 1 minute. Find the probability that a randomly selected college student will take between 2.5 and...

The length of time it takes college students to find a parking spot in the library parking lot follows a normal distribution with a mean of 5.5 minutes and a standard deviation of 1 minute. Find the probability that a randomly selected college student will take between 4.0 and...

2500 students take a college entrance exam. The scores on the exam have an approximate normal distribution with mean u = 52 points and a standard deviation o = 11 points. Estimate the percentage of students scoring 52 points or more. ^ How would you do this?

A normal distribution has a mean of 98 and a standard deviation of 6. What is the probability that a randomly selected xvalue from the distribution is at least 80?

Students were given an exam with 300 multiplechoice questions. The distribution of the scores was normal and mean was 195 with a standard deviation of 30. You may find it helpful to draw out this distribution before answering the questions below What were the scores of the ...

For a normal distribution where mx= 80 and sx= 10, the distribution model fits well to test scores of N = 20000 students.

Suppose that the ages of students at a particular university average 26 years with a standard deviation of 2.8 years. Consider the sampling distribution of the sample mean age of students in a sample of n = 49. The standard deviation of the sampling distribution is

A normal distribution has a mean of 20 and a standard deviation of 3.What is the probability that a randomly selected xvalue from the distribution is: A)at least 14? B)at most 26? C)Between 8 and 23?


Large group of students took a test in English and the final grades have a mean of 75 and a standard deviation of 8. If we can approximate the distribution of these grades by a normal distribution. What percentage of the students (ii) Should pass the test (grades >= 60) (...

Large group of students took a test in English and the final grades have a mean of 75 and a standard deviation of 8. If we can approximate the distribution of these grades by a normal distribution. What percentage of the students (ii) Should pass the test (grades >= 60) (...

If we know that the length of time it takes a college student to find a parking spot in the library parking lot follows a normal distribution with a mean of 3.5 minutes and a standard deviation of 1 minute, find the point in the distribution in which 75.8% of the college ...

Suppose x has a moundshaped distribution with sigma = 9 . A random sample of size 36 has sample mean 20. Is it appropriate to use a normal distribution to compute a confidence interval for the population mean m? Explain. Find a 95% confidence interval for m. Explain the ...

if np >5 and nq>5 estimate P (fewer than 4) with n=13 p=0.4 by using normal distribution as an approximate to the binomial distribution if np <5 or nq< then state that the normal approximation is not suitable

I have a couple of questions that need reviewI've answered them, but I'm not sure if I'm correct. 1.)Suppose you interview 10 randomly selected workers and ask how many miles they commute to work. You'll compute the sample mean commute distance. Now imagine repeating the ...

Statistics: Analyze student exam scores Students were given an exam with 300 multiple choice questions. The distribution of the scores were normal and the mean was 195 with a standard deviation of 30. you may find it helpful to draw out this distribution before answering the ...

Trying to finish an assignment: What happens to the power of the z test when the standard deviation increases? and Is the shape of a sampling distribution always the same as that of the null hypothesis population? Thanks! As the SD increases, the exactness of the estimate of a...

When finding a confidence interval for a population mean based on a sample of size 11, which assumption is made? The standard deviation is fixed. The sampling distribution of z is normal. The sampling distribution of the sample means is approximately normal. There is no ...

Students were given an exam with 300 multiplechoice questions. The distribution of the scores was normal and mean was 195 with a standard deviation of 30. What was the score of students who scored in the middle of the class? (50% did better, 50% did worse).


Students were given an exam with 300 multiplechoice questions. The distribution of the scores was normal and mean was 195 with a standard deviation of 30. What was the score of students who scored in the middle of the class? (50% did better, 50% did worse).

A student group claims that firstyear students at a university must study 2.5 hours (150 minutes) per night during the school week. A skeptic suspects that they study less than that on the average. A class survey finds that the average study time claimed by 269 students is = ...

Kind attention Psydag: A random sample of size 20 from a normal population with sample mean 42 and sample standard deviation of 6 . To test the hypothesis the population mean 44 at 5% level of significance , find the pvalue and comment Clarification: The sample size is 20 ...

A class survey in a large class for firstyear college students asked, “About how many minutes do you study on a typical weeknight?” The mean response of the 463 students was = 118 minutes. Suppose that we know that the study time follows a Normal distribution with ...

How do I answer: A normal distribution has a standard deviation equal to 39. What is the mean of this normal distribution if the probability of scoring above x = 209 is 0.0228

True or false: as then number in the sample becomes larger and larger (assuming it means as the sample gets larger and larger), then the mean of the sampling distribution is equal to the population distribution for any normal population. Is it false? That it would be ...

True or false: as then number in the sample becomes larger and larger (assuming it means as the sample gets larger and larger), then the mean of the sampling distribution is equal to the population distribution for any normal population. Is it false? That it would be ...

A normal distribution has a standard deviation equal to 23. What is the mean of this normal distribution if the probability of scoring above x = 181? record to 1 decimal place

I have a problem on standard deviation, and I will need some help with it. Problem: Each professor in an English class give an A to students scoring above 90 and a F to those scoring below 60. Professor 1 has a normal distribution with a mean of 74 and standard deviation 7 ...

A question on a test is answered correctly by 22% of the students find the probability that in the next 150 students there will be more than 40 correct answers use the normal distribution


The same calculus exam has a normal distribution with a mean of 76 and a standard deviation of 6. Find the percentage of students that scored between 65 and 90.

Among a random sample of 500 college students, the mean number of hours worked per week at noncollege related jobs is 14.6. This mean lies 0.4 standard deviations below the mean of the sampling distribution. If a second sample of 500 students is selected, what is the ...

Assume it is known that the probability of birth is equal in all months. What is the probability that in the STAT class of 120 students, exactly 20 students have their birthdays in either August or September? Solve using (i) the exact Binomial distribution, (ii) the Normal ...

If we know that the length of time it takes an MBA student to find a parking spot near the DePaul Center follows a normal distribution with a mean of 3.5 minutes and a standard deviation of 1 minute, find the point in the distribution that 75.8% of the MBA students exceed when...

A normal distribution has a mean of 100 and standard deviation of 20. What is the probability of randomly selecting a score less than 130 from this distribution? a, p=0.9032 b, p=0.9332 c, p=0.0968 d, p=0.0668

Sampling Distribution Complete solutions and illustrations are required. 1.The average annual salary for all U.S. teachers is $29,863. Assume that the distribution is normal and the standard deviation is $5,200. a.Find the probability that a randomly selected teacher earns at ...

Statistical Abstracts (117th edition) reports sale price of unleaded gasoline (in cents per gallon) at the refinery. The distribution is moundshaped with mean μ = 80.04 cents per gallon and standard deviation, σ = 4.74 cents per gallon. (a) Are we likely to get good...

Assume it is known that the probability of birth is equal in all months. What is the probability that in the STAT 1025 class of 120 students, exactly 20 students have their birthdays in either August or September? Solve using (i) the exact Binomial distribution, (ii) the ...

Assume it is known that the probability of birth is equal in all months. What is the probability that in the STAT 1025 class of 120 students, exactly 20 students have their birthdays in either August or September? Solve using (i) the exact Binomial distribution, (ii) the ...

Assume it is known that the probability of birth is equal in all months. What is the probability that in the STAT 1025 class of 120 students, exactly 20 students have their birthdays in either August or September? Solve using (i) the exact Binomial distribution, (ii) the ...


A student claims the average amount of time spent studying for an exam is less than or equal to 120 minutes. A random sample of 101 students is drawn from a normal distribution. The sample mean is 140 with a sample standard deviation of 20. Test the claim with a .01 level of ...

In the past a certain college has found that 35% of the students will grad within 4 years. A random sample of 450 students at this college is taken and going to be followed until graduation. A. What is the sampling distribution of the statistic of interest? B. What is the ...

Let T1,T2,…,Tn be i.i.d. observations, each drawn from a common normal distribution with mean zero. With probability 1/2 this normal distribution has variance 1, and with probability 1/2 it has variance 4. Based on the observed values t1,t2,…,tn, we use the MAP rule to ...

A government report looked at the amount borrowed for college by students who graduated in 2000 and had taken out student loans. The mean amount was = $ 17 , 776 and the standard deviation was s = $12,034. The quartiles were Q 1 = $9900, M = $15,532, and Q 3 = $22,500. The ...

A professor at a local college noted that the grades of his students were normally distributed with an average percentage of 74 and a population standard deviation of 10. He found that 6.3% of his students received A's while 2.5% of his students failed the course and received ...
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