Question

Suppose the scores on a certain midterm were not very high and their probability density function...

Suppose the scores on a certain midterm were not very high and their probability density function was ?(?) = 1 /14480 ⋅ (3? + 1), 20 ≤ ? ≤ 100.

a) What is the expected value of the scores, ?[?]?

b) What is the standard deviation of the scores, ??[?]?

c) What as the 90th percentile? i.e. Find c such that ?[? ≤ ?] = 0.9

Math   Statistics-And-Probability   
0 0
Add a commentTranscribed image text
Next >

Homework Answers

Answer #1

0 0
Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Log In

Sign Up

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
Alice and Betty are going to take the second midterm exam. Suppose their scores will have...
Alice and Betty are going to take the second midterm exam. Suppose their scores will have normal distributions that center at their first midterm exam scores, with the same standard deviation 5. Suppose that exam scores do not have upper bounds. If they got 38 and 42 in the first midterm, respectively, then what is the probability that both of their second midterm scores will be above 45?
Suppose that your statistics professor tells you that the scores on a midterm exam were approximately...
Suppose that your statistics professor tells you that the scores on a midterm exam were approximately normally distributed with a mean of 78 and a standard deviation of 7. The top 15% of all scores have been designated A’s. What is the minimum score that you must earn in order to receive a letter grade A.
3. A statistical analysis is made of the midterm and final scores in a large course,...
3. A statistical analysis is made of the midterm and final scores in a large course, with the following results: (20 points) Average midterm score = 65, SD = 10, Average final score = 65, SD = 12, r = 0.6 The scatter diagram is football shaped. a. About what percentage of the class final scores above 70? ((5 points) b. A student midterm was 75. Predict his final score (5 points) c. Suppose the percentile rank of midterm score...
1. Suppose the random variables ?? and ?? have the joint probability density function, ??(??,??) =(4??...
1. Suppose the random variables ?? and ?? have the joint probability density function, ??(??,??) =(4?? + 2??) / 75 ?????? 0 < ?? < 3 ?????? 0 < ?? < ?? + 1 a) Determine the marginal probability density function of ??.    b) Determine the conditional probability of ?? given ?? = 2. 2. To estimate the average monthly rent for 1 bedroom apartments, 13 complexes were randomly selected in Orlando. The mean cost is $970 with a...
For a certain standardized placement test, it was found that the scores were normally distributed, with...
For a certain standardized placement test, it was found that the scores were normally distributed, with a mean of 250 and a standard deviation of 30. Suppose that this test is given to 1000 students. (Recall that 34% of z-scores lie between 0 and 1, 13.5% lie between 1 and 2, and 2.5% are greater than 2.) (a) How many are expected to make scores between 220 and 280? students (b) How many are expected to score above 310? students...
For a certain standardized placement test, it was found that the scores were normally distributed, with...
For a certain standardized placement test, it was found that the scores were normally distributed, with a mean of 250 and a standard deviation of 35. Suppose that this test is given to 1000 students. (Recall that 34% of z-scores lie between 0 and 1, 13.5% lie between 1 and 2, and 2.5% are greater than 2. A)How many are expected to make scores between 220 and 280? B)How many are expected to score above 310? C) What is the...
Suppose that the distribution of scores on an exam is mound shaped and approximately symmetric. The...
Suppose that the distribution of scores on an exam is mound shaped and approximately symmetric. The exam scores have a mean of 100 and the 16th percentile is 75. (Use the Empirical Rule.) (a) What is the 84th percentile? (b) What is the approximate value of the standard deviation of exam scores? (c) What is the z-score for an exam score of 90? (d) What percentile corresponds to an exam score of 150? % (e) Do you think there were...
Compound probability density function of random variables x and ? ??, ? (?, ?) = {...
Compound probability density function of random variables x and ? ??, ? (?, ?) = { 6/7 (?*2 + ??/2), 0 <? <2, 0 <? <1 (? ,  other It is given as. According to this (a) Show that this function is a probability density function. (b) Find the marginal probability density function of ?. (c) Calculate the probability ? {?> ?}. (d) Find the expected value of ? [?].
Compound probability density function of random variables ? and ? ??, ? (?, ?) = (6/7...
Compound probability density function of random variables ? and ? ??, ? (?, ?) = (6/7 (? * y + (? * ?) / 2), 0 <? <2, 0 <? <1?, other It is given as. According to this (a) Show that this function is a probability density function. (b) Find the marginal probability density function of ?. (c) Calculate the probability ? {?> ?}. (d) Find the expected value of ? [?].
The Scholastic Aptitude Test (SAT) scores in mathematics at a certain high school are normally distributed,...
The Scholastic Aptitude Test (SAT) scores in mathematics at a certain high school are normally distributed, with a mean of 550 and a standard deviation of 100. What is the probability that an individual chosen at random has the following scores? (Round your answers to four decimal places.) (a) greater than 650 (b) less than 450 (c) between 600 and 750 Use the table of areas under the standard normal curve to find the probability that a z-score from the...
ADVERTISEMENT
Need Online Homework Help?

Get Answers For Free
Most questions answered within 1 hours.

Ask a Question
ADVERTISEMENT