A binary message m, where m is equal either to 0 or to 1, is sent over an information channel. Assume that if m = 0, the value s = −1.5 is sent, and if m = 1, the value s = 1.5 is sent. The value received is X, where X = s + E, and E ∼ N(0, 0.66). If X ≤ 0.5, then the receiver concludes that m = 0, and if X > 0.5, then the receiver concludes that m = 1.
If the true message is m = 0, what is the probability of an error, that is, what is the probability that the receiver concludes that m = 1? Round the answer to four decimal places.
If the true message is m = 1, what is the probability of an error, that is, what is the probability that the receiver concludes that m = 0?
A string consisting of 60 1s and 40 0s will be sent. A bit is chosen at random from this string. What is the probability that it will be received correctly?
Refer to part (c). A bit is chosen at random from the received string. Given that this bit is 1, what is the probability that the bit sent was 0?
Refer to part (c). A bit is chosen at random from the received string. Given that this bit is 0, what is the probability that the bit sent was 1?
In: Statistics and Probability
Every day you flip a fair coin four times and if it is heads all four times, you give a dollar to charity. In a year with 365 days, what is your expected annual donation to charity and what is the variance?
In: Statistics and Probability
Consider the following hypothesis test.
H0: p = 0.30
Ha: p ≠ 0.30
A sample of 400 provided a sample proportion p = 0.275.
(a)
Compute the value of the test statistic. (Round your answer to two decimal places.) ______
(b) What is the p-value? (Round your answer to four decimal places.) p-value =_____
(c) At α = 0.05, what is your conclusion?
Reject H0. There is insufficient evidence to conclude that p ≠ 0.30.
Reject H0. There is sufficient evidence to conclude that p ≠ 0.30.
Do not reject H0. There is sufficient evidence to conclude that p ≠ 0.30.
Do not reject H0. There is insufficient evidence to conclude that p ≠ 0.30.
(d)
What is the rejection rule using the critical value? (Round your answer to two decimal places. If the test is one-tailed, enter NONE for the unused tail.)
test statistic ≤ ______
test statistic ≥ ______
What is your conclusion?
Reject H0. There is insufficient evidence to conclude that p ≠ 0.30.
Reject H0. There is sufficient evidence to conclude that p ≠ 0.30.
Do not reject H0. There is sufficient evidence to conclude that p ≠ 0.30.
Do not reject H0. There is insufficient evidence to conclude that p ≠ 0.30.
In: Statistics and Probability
The time (in minutes) required for six‑year old children to assemble a certain toy is believed to be normally distributed with a known standard deviation of 3.0. The data in Table B gives the assembly times for a random sample of 25 children.
8. What was the mean assembly time for this sample of 25 six‑year old children? |
24.3792 |
9. What was the estimated standard deviation? |
3.061977 |
10. What was the margin of error of the estimate for a 90% confidence interval? |
11. What was the lower limit of the 90% confidence interval for average assembly time? |
12. What was the upper limit of the 90% confidence interval for average assembly time? |
Table B:
25.11 |
25.49 |
23.45 |
26 |
24.23 |
18.95 |
25.16 |
30.77 |
20.87 |
22.85 |
23.11 |
21.21 |
22.25 |
24.68 |
21.21 |
25.81 |
30.4 |
26.02 |
23.35 |
25.18 |
30.75 |
25.26 |
21.61 |
25.29 |
20.47 |
Hi, I need help with questions 10, 11 and 12. Is there a way I can do them on excel? Thanks!
In: Statistics and Probability
Consider the following gasoline sales time series. If needed, round your answers to two-decimal digits.
Week | Sales (1,000s of gallons) |
1 | 17 |
2 | 21 |
3 | 16 |
4 | 24 |
5 | 17 |
6 | 18 |
7 | 22 |
8 | 20 |
9 | 21 |
10 | 19 |
11 | 16 |
12 | 25 |
(a) | Show the exponential smoothing forecasts using α = 0.1, and α = 0.2. | |||||||||
|
||||||||||
(b) | Applying the MSE measure of forecast accuracy, would you prefer a smoothing constant of α = 0.1 or α = 0.2 for the gasoline sales time series? | |||||||||
An - Select your answer -α = 0.1α = 0.2Item 3 smoothing constant provides the more accurate forecast, with an overall MSE of . | ||||||||||
(c) | Are the results the same if you apply MAE as the measure of accuracy? | |||||||||
An - Select your answer -α = 0.1α = 0.2Item 5 smoothing constant provides the more accurate forecast, with an overall MAE of . | ||||||||||
(d) | What are the results if MAPE is used? | |||||||||
An - Select your answer -α = 0.1α = 0.2Item 7 smoothing constant provides the more accurate forecast, with an overall MAPE of . |
In: Statistics and Probability
Is there a positive relationship between grit and GPA in high school seniors? A researcher examined this issue by having students beginning their senior year of high school complete a grit inventory using a Likert-based scale (range 1 – 7), where higher numbers indicate more “grit”. GPA was self-reported (scale 0 – 4.0). Enter the data shown here into SPSS to assess whether there is a positive relationship between grit and GPA.
Grit |
GPA |
6.5 |
4.0 |
4.0 |
3.1 |
3.7 |
2.7 |
5.8 |
3.5 |
4.7 |
3.1 |
5.5 |
3.3 |
3.9 |
2.7 |
1.1 |
2.8 |
3.5 |
3.1 |
2.7 |
2.6 |
5.1 |
3.8 |
3.2 |
2.2 |
5.6 |
2.8 |
6.1 |
2.5 |
GPA |
4.0 |
3.1 |
2.7 |
3.5 |
3.1 |
3.3 |
2.7 |
2.8 |
3.1 |
2.6 |
3.8 |
2.2 |
2.8 |
2.5 |
Grit |
6.5 |
4.0 |
3.7 |
5.8 |
4.7 |
5.5 |
3.9 |
1.1 |
3.5 |
2.7 |
5.1 |
3.2 |
5.6 |
6.1 |
In: Statistics and Probability
A savvy business owner wanted to assess whether the type of fragrance influenced the amount of money spent. He tried peppermint, lavender, male cologne, and a floral perfume in his four stores. Amount of money spent (in hundreds) is reported for each type of fragrance. Conduct a one-way repeated measures ANOVA to determine whether fragrance influences total amount of money spent.
Peppermint |
Lavender |
Cologne |
Floral |
4.2 |
3.3 |
5.1 |
3.9 |
5.1 |
1.8 |
4.9 |
4.3 |
4.8 |
3.0 |
3.2 |
3.5 |
6.2 |
3.2 |
4.0 |
3.7 |
3.1 |
2.3 |
3.8 |
2.1 |
4.5 |
2.9 |
4.7 |
2.3 |
4.8 |
3.5 |
3.8 |
1.0 |
3.7 |
4.7 |
4.1 |
2.8 |
2.8 |
3.1 |
3.5 |
4.2 |
In: Statistics and Probability
The body temperatures of a group of healthy adults have a bell-shaped distribution with a mean of 98.08degreesF and a standard deviation of 0.63degreesF. Using the empirical rule, find each approximate percentage below. a. What is the approximate percentage of healthy adults with body temperatures within 1 standard deviation of the mean, or between 97.45degreesF and 98.71degreesF? b. What is the approximate percentage of healthy adults with body temperatures between 96.19degreesF and 99.97degreesF?
In: Statistics and Probability
6. Research Question: Is there a higher percentage of Christians among CSU students than among USC students?
To test this I set up the hypothesis test
H0 : pCSU = pUSC Ha : pCSU > pUSC
This test gave a p-value of 0.023.
(a) Give your conclusion in context for this test using α = 0.05. (Your conclusion should be written so that a lay person could understand.)
(b) Give your conclusion in context for this test using α = 0.01. (Your conclusion should be written so that a lay person could understand.)
(c) Using the same sample data as in the hypothesis test, would a 95% confidence interval for pCSU − pUSC include the value 0? Explain.
Suppose someone you know and their spouse has been trying to start a family for a couple of years. The wife thinks she may be pregnant, so there will be a pregnancy test. Suppose the test has the hypotheses
H0 : Wife is pregnant.
Ha : Wife is not pregnant. (
(d) What are the consequences of making a Type I error?
(e) What are the consequences of making a Type II error?
In: Statistics and Probability
The management of Hatman Toy Company is trying to determine the best production and overtime schedule for the coming month to attain maximum profit. The company makes two toy items. Each of the two toys needs to go through three departments (A: Casting, B: Painting, C: Costume) to be completed. The following table shows the amount of time (in minutes) each department needs to process each toy item: Product (minutes/unit) Department Toy 1 Toy 2 A 60 21 B 18 12 C 12 30 Toy item 1 is sold at $30 profit/unit and toy item 2 is sold at $15 profit/unit. Departments A, B, and C have a total of 100, 36, and 50 hours of (regular) labor time available each month for production. However, the company can schedule some overtime in each department at an additional cost. Each hour of overtime costs $18 in department A, $22.50 in department B, and $12 in department C. Up to a maximum of 10, 6, and 8 hours of overtime can be scheduled in departments A, B, and C, respectively. a) Write a mathematical formulation of the problem, which simultaneously determines how many units of each toy item to make, and how many hours of overtime should be used in each department (Hint: So we are trying to figure out 5 numbers in total). Clearly define your decision variables (full sentence!), and then write the objective function and constraints algebraically?
In: Statistics and Probability
An article investigated the consumption of caffeine among women. A sample of 52 women were asked to monitor their caffeine intake over the course of one day. The mean amount of caffeine consumed in the sample of women was 226.553 mg with a standard deviation of 229.462 mg. In the article, researchers would like to include a 99% confidence interval.
In: Statistics and Probability
The time required to assemble an electronic component is normally distributed with a mean and a standard deviation of 15 minutes and 8 minutes, respectively.
a) Find the probability that a randomly picked assembly takes between 12 and 19 minutes. (Round "z" value to 2 decimal places and final answer to 4 decimal places.)
b) it is unusual for the assembly time to be above 28 minutes or below 5 minutes. What proportion of assembly times fall in these unusual categories? (Round "z" value to 2 decimal places and final answer to 4 decimal places.)
In: Statistics and Probability
In New York City, a study was conducted to evaluate whether any information that is available at the time of birth can be used to identify children with special educational needs. In a random sample of 45 third-graders enrolled in the special education program of the public school system, 4 have mothers who have had more than 12 years of schooling.
A) Construct a 90% CI for the population proportion of children
with special educational needs whose mothers have had more than 12
years of schooling.
B) In 1980, 22% of all third-graders enrolled in the NYC public
school system had mothers who had more than 12 years of schooling.
Suppose you wish to know whether this proportion is the same for
children in the special education program. What are the null and
alternative hypotheses of the appropriate test?
C) Conduct the test at the 0.05 level of significance
Should use exact confidence interval and exact test in parts a and c. Please include your R commands for these parts.
In: Statistics and Probability
Determine the uniformly most powerful test of H0:θ≤1 versus H1:θ >1 for a random sample of 25 from N(0,θ), at the significance level α=.05.
In: Statistics and Probability
Salaries for teachers in a particular elementary school district are normally distributed with a mean of $42,000 and a standard deviation of $5,700. We randomly survey ten teachers from that district. (Round your answers to the nearest dollar.)
(a) Find the 90th percentile for an individual
teacher's salary.
$ =
(b) Find the 90th percentile for the average teacher's
salary.
$ =
In: Statistics and Probability