The personnel office at a large electronics firm regularly schedules job interviews and maintains records of the interviews. From the past records, they have found that the length of a first interview is normally distributed, with mean μ = 38 minutes and standard deviation σ = 6 minutes. (Round your answers to four decimal places.)
(a) What is the probability that a first interview will last 40
minutes or longer?
(b) Seventeen first interviews are usually scheduled per day. What
is the probability that the average length of time for the
seventeen interviews will be 40 minutes or longer?
In: Math
A national grocer’s magazine reports the typical shopper spends 10 minutes in line waiting to check out. A sample of 20 shoppers at the local Farmer Jack’s showed a mean of 9.6 minutes with a standard deviation of 3.7 minutes. Is the waiting time at the local Farmer Jack’s less than that reported in the national magazine? Use the 0.025 significance level. What is the decision rule? (Negative amount should be indicated by a minus sign. Round your answer to 3 decimal places.) Compute the value of the test statistic. (Negative amount should be indicated by a minus sign. Round your answer to 2 decimal places.) What is your decision regarding H0? Reject H0 Do not reject H0
In: Math
A sample of 44 observations is selected from a normal population. The sample mean is 24, and the population standard deviation is 3. Conduct the following test of hypothesis using the 0.05 significance level. H0: μ ≤ 23 H1: μ > 23 Is this a one- or two-tailed test? One-tailed test Two-tailed test What is the decision rule? Reject H0 when z > 1.645 Reject H0 when z ≤ 1.645 What is the value of the test statistic? (Round your answer to 2 decimal places.) What is your decision regarding H0? Reject H0 Fail to reject H0 e-1. What is the p-value? (Round your answer to 4 decimal places.) e-2. Interpret the p-value? (Round your final answer to 2 decimal places.)
In: Math
In a study of cell phone use and brain hemispheric dominance, an Internet survey was e-mailed to 2446 subjects randomly selected from an online group involved with ears. 1083 surveys were returned. Construct a 99% confidence interval for the proportion of returned survey.
In: Math
Question 1 options:
According to the February 2008 Federal Trade Commission report on consumer fraud and identity theft, 23% of all complaints in 2007 were for identity theft. In that year, Alaska had 321 complaints of identity theft out of 1,432 consumer complaints ("Consumer fraud and," 2008). Does this data provide enough evidence to show that Alaska had a lower proportion of identity theft than 23%? Test at the 5% level.
(i) Which of the following statements correctly defines the null hypothesis HO?
A. μ = 321
B. p < 0.23
C. p = 0.23
D. μ < 321
Enter letter corresponding to correct answer
(ii) Which of the following statements correctly defines the alternative hypothesis HA?
A. μ = 321
B. p < 0.23
C. p = 0.23
D. μ < 321
Enter letter corresponding to correct answer
(iii) Enter the level of significance α used for this test:
Enter in decimal form. Examples of correctly entered answers: 0.01 0.02 0.05 0.10
(iv) Determine pˆ{"version":"1.1","math":"<math xmlns="http://www.w3.org/1998/Math/MathML"><mfenced><mi mathvariant="bold">iv</mi></mfenced><mo mathvariant="bold"> </mo><mo mathvariant="bold"> </mo><mi mathvariant="bold">Determine</mi><mo mathvariant="bold"> </mo><mover><mi mathvariant="bold">p</mi><mo mathvariant="bold">^</mo></mover></math>"}
Enter in decimal form to nearest ten-thousandth. Examples of correctly entered answers:
0.0001 0.0020 0.0500 0.3000 0.7115
(v) Do values for np and nq both exceed 5? Enter YES or NO for answer
(vi) Calculate and enter test statistic
Enter value in decimal form rounded to nearest thousandth, with appropriate sign (no spaces). Examples of correctly entered answers:
–2.014 –0.370 +0.600 +1.009
(vii) Using tables, calculator, or spreadsheet: Determine and enter p-value corresponding to test statistic.
Enter value in decimal form rounded to nearest thousandth. Examples of correctly entered answers:
0.000 0.001 0.030 0.600 0.814 1.000
(viii) Comparing p-value and α value, which is the correct decision to make for this hypothesis test?
A. Reject Ho
B. Fail to reject Ho
C. Accept Ho
D. Accept HA
Enter letter corresponding to correct answer.
(ix) Select the statement that most correctly interprets the result of this test:
A. The result is statistically significant at .05 level of significance. Evidence supports the claim that the proportion of complaints due to identity theft in Alaska is less than 23%.
B. The result is statistically significant at .05 level of significance. There is not enough evidence to show that the proportion of complaints due to identity theft in Alaska is not less than 23%.
C. The result is not statistically significant at .05 level of significance. There is not enough evidence to show that the proportion of complaints due to identity theft in Alaska is less than 23%.
D. The result is not statistically significant at .05 level of significance. Evidence supports the claim that the proportion of complaints due to identity theft in Alaska is not less than 23%.
Enter letter corresponding to most correct answer
In: Math
Anystate Auto Insurance Company took a random sample of 360 insurance claims paid out during a 1-year period. The average claim paid was $1535. Assume σ = $252. Find a 0.90 confidence interval for the mean claim payment. (Round your answers to two decimal places.) lower limit $ upper limit $ Find a 0.99 confidence interval for the mean claim payment. (Round your answers to two decimal places.
Find a 0.90 confidence interval for the mean claim payment. (Round your answers to two decimal places.)
| lower limit | $ |
| upper limit |
$ |
Find a 0.99 confidence interval for the mean claim payment. (Round your answers to two decimal places.)
| lower limit | $ |
| upper limit | $ |
In: Math
Three experiments investigating the relation between need for cognitive closure and persuasion were performed. Part of the study involved administering a "need for closure scale" to a group of students enrolled in an introductory psychology course. The "need for closure scale" has scores ranging from 101 to 201. For the 79 students in the highest quartile of the distribution, the mean score was x = 176.50. Assume a population standard deviation of σ = 7.47. These students were all classified as high on their need for closure. Assume that the 79 students represent a random sample of all students who are classified as high on their need for closure. Find a 95% confidence interval for the population mean score μ on the "need for closure scale" for all students with a high need for closure. (Round your answers to two decimal places.)
lower limit
upper limit
In: Math
In each of the following cases, compute 95 percent, 98 percent,
and 99 percent confidence intervals for the population proportion
p.
(a) pˆp^ = .6 and n = 100
(Round your answers to 3 decimal
places.)
| 95 percent confidence intervals is [, ] | |
| 98 percent confidence intervals is [, ] | |
| 99 percent confidence intervals is [, ] | |
(b) pˆp^ = .5 and n = 299. (Round
your answers to 3 decimal places.)
| 95 percent confidence intervals is [, ] | |
| 98 percent confidence intervals is [, ] | |
| 99 percent confidence intervals is [, ] | |
(c) pˆp^ = .7 and n = 121. (Round your answers to 3 decimal places.)
| 95 percent confidence intervals is [, ] | |
| 98 percent confidence intervals is [, ] | |
| 99 percent confidence intervals is [, ] | |
(d) pˆp^ = .8 and n = 56. (Round
your answers to 3 decimal places.)
| 95 percent confidence intervals is [, ] | |
| 98 percent confidence intervals is [, ] | |
| 99 percent confidence intervals is [, ] | |
In: Math
Two 6-sided dice are rolled. Let X be the larger of the two numbers showing. For each i from 1 to 6, find the probability that X = i.
In: Math
In an article in the Journal of Advertising, Weinberger and Spotts compare the use of humor in television ads in the United States and the United Kingdom. They found that a substantially greater percentage of U.K. ads use humor.
(a) Suppose that a random sample of 387
television ads in the United Kingdom reveals that 131 of these ads
use humor. Find a point estimate of and a 95 percent confidence
interval for the proportion of all U.K. television ads that use
humor. (Round your answers to 3 decimal
places.)
| pˆp^ = |
| The 95 percent confidence interval is [,]. |
(b) Suppose a random sample of 493 television
ads in the United States reveals that 134 of these ads use humor.
Find a point estimate of and a 95 percent confidence interval for
the proportion of all U.S. television ads that use humor.
(Round your answers to 3 decimal
places.)
| pˆp^ = |
| The 95 percent confidence interval is [,]. |
(c) Do the confidence intervals you computed in
parts a and b suggest that a greater percentage
of U.K. ads use humor?
(Click to select)YesNo , the U.K. 95 percent confidence interval is
(Click to select)not aboveabove the maximum value
in the confidence interval for the U.S.
In: Math
Briefly explain specifically why categorical and quantitative variables require different methods in order to describe their distributions.
A correct answer will accurately address BOTH types of variables and clearly explain the REASONS these two types of variables REQUIRE different methods.
In: Math
street performer offers you a chance to play his game for the low price of $10.
His game involves you pushing two different buttons. One of the buttons, when pushed, has a 10% chance of winning you $40;
and the oth er button, when pushed, has a 20% chance of winning you $25. You are allowed two button presses( e ither pushing the same button twice or pushing each button once) in a single game.
Is it worth playing?
In: Math
1. Liv attends “Happy Days” preschool. The preschool ran assessments on the children’s motor skills (such as ability to tie a shoe), social skills (such as sharing and saying “please” and “thank you”), and school readiness (such as knowing ABCs and basic counting). The motor skills test has a class mean of 6 with a standard deviation of 1, the social skills test has a class mean of 10 with a standard deviation of 2, and the school readiness test has a mean of 16 with a standard deviation of 4. Liv’s parents are given a report that indicates that her z score for motor skills is –1.11, for social skills it is 0.25, and for school readiness it is 0.
a. The parents do not know what z scores are. Clearly define for them what a z score measures and the advantages of using z scores compared to raw scores.
b. What does a z score = –1.11 mean? A z score of 0.25? A z score of 0?
c. What are Liv’s raw scores on each test?
In: Math
In: Math
b.The lead engineer on the design team has requested that you match the reliability of the parallel system with a series system. All three of the valves in series will have the same probability of functioning correctly. What does this probability need to be to equal the probability of the parallel system?
c. Comment on the advantages and disadvantages of using parallel systems in aircraft design.
Based on the experimental data, it was determined that the probability of the three valves functioning correctly are:
Valve 1: 95% • Valve 2: 94% • Valve 3: 92%
In: Math