A coin was flipped 60 times and came up heads 38 times. (a) At the .10 level of significance, is the coined biased towards heads? Show your decision rule and calculations. (b) Calculate a p-value and interpret it.
1. Clark Heter is an industrial engineer at Lyons Products. He would like to determine whether there are more units produced on the night shift than on the days shift. Assume the populations standard deviation for the number of units produced on the days shift is 21 and is 28 on the night shift. A sample of 54 day shift workers
Does lovastatin (a cholesterol lowering drug) reduce the risk of heart attack? In a Texas study, researchers gave lovastatin to 2,325 people and an inactive substitute to 2,081 people (averge age 58). After 5 years, 57 of the lovastatin group had suffered a heart attack, compared with 97 for the inactive pill. a) state the appro
In Dallas some fire trucks were painted yellow (instead of red)to heighten their visibility. During a test period the fleet of red fire trucks made 153,348 runs and had 20 accidents, while the fleet of yellow fire trucks made 135,035 runds and had 4 accidents. At a=.01, did the yellow fire trucks have a significantly lower accid
Why are proportions handled differently than means in estimating procedures?
How tall are college hockey players? The average height has been 68.3 inches. A random sample of 14 hockey players gave a mean height of 69.1 inches. We may assume that x has a normal distribution with σ = 0.9 inch. Does this indicate that the populations mean height is different from 68.3 inches? Use 5% level of signi
1. Can the formal hypothesis testing approach be used for non parametric tests? a) How are parametric and nonparametric statistics different? b) How are parametric and nonparametric statistics similar?
Using observations on each variable, a computer program generated the following multiple regression model: If the standard errors of the coefficients of the independent variables are, respectively, and , can you conclude that the independent variable is needed in the regression model? Let and denote the coeffici
A consumer products testing group is evaluating two competing brands of tires, Brand 1 and Brand 2. Tread wear can vary considerably depending on the type of car, and the group is trying to eliminate this effect by installing the two brands on the same random sample of cars. In particular, each car has one tire of each brand on
Why is statistical significance not necessarily of practical important difference to a business decision? Give an example and explain. Why do statisticians play only a limited role in deciding whether statistical significance requires a business action?
Is there an association or correlation between the variables 'attached garage' and 'township.' Use the 0.05 significance level. Please see the attached file.
High levels of cockpit noise in an aircraft can damage the hearing of pilots who are exposed to this hazard for many hours. A Boeing 727 co-pilot collected 61 noise observations using a handheld sound meter. Noise level is defined as "Low" (under 88 decibels), "Medium" (88 to 91 decibels), or "High" (92 decibels or more). There
A physician claims that joggers' maximal volume oxygen uptake is greater than the average of all adults. A sample of 15 joggers has a mean of 43.6 milliliters per kilogram (ml/kg) and a standard deviation of 6 ml/kg. If the average of all adults is 36.7 ml/kg, is there enough evidence to support the physician's claim at a = 0.05
A sample of 25 concession stand purchases at the October 22 matinee of Bride of Chucky showed a mean purchase of $5.29 with a standard deviation of $3.02. For the October 26 evening showing of the same movie, for a sample of 25 purchases the mean was $5.12 with a standard deviation of $2.14. The means appear to be very close, bu
10.46 To test the hypothesis that students who finish an exam first get better grades, Professor Hardtack kept track of the order in which papers were handed in. The first 25 papers showed a mean score of 77.1 with a standard deviation of 19.6, while the last 24 papers handed in showed a mean score of 69.3 with a standard deviat
10.44 Does lovastatin (a cholesterol-lowering drug) reduce the risk of heart attack? In a Texas study, researchers gave lovastatin to 2,325 people and an inactive substitute to 2,081 people (average age 58). After 5 years, 57 of the lovastatin group had suffered a heart attack, compared with 97 for the inactive pill. (a) State t
In Dallas, some fire trucks were painted yellow (instead of red) to heighten their visibility. During a test period, the fleet of red fire trucks made 153,348 runs and had 20 accidents, while the fleet of yellow fire trucks made 135,035 runs and had 4 accidents. At alpha = .01, did the yellow fire trucks have a significantly low
Problem: 5-Dec Alaska American America West British Continental 7.74% 7.67% -0.89% -2.52% 4.12% Delta JetBlue Northwest Southwest US Airways 4.45% 3.14% 4.84% 3.53% No Change Estimate the variance of the percent change in airline stock 6-Dec
A food processor specifies the mean weight of a product as 200g. A random sample of 20 has a mean of 195g and a standard deviation of 15g. Does this evidence suggest that the mean weight is too low?
1. The mean life of a computer disk drive is 2,000 hours. The standard deviation is 140 hours. Assuming the life-time of the drives to be normally distributed, find the probability of a disk drive lasting more than 1,800 hours. a. .4236 b. .9236 c. .8472 d. .5764 e. .2118 f. None of the above. 2. T
Last year a trial survey found that 65% of houses in a town had a computer. A follow up survey wants to find the actual number of houses with a computer to within 3% with a 95% confidence interval. How many houses should it survey?
A coin was flipped 60 times and came up heads 38 times. a) At the 0.10 level of significance, is the coin biased toward heads? Show your decision rule and calculations. b) Calculate the p-value and interpret it.
Faced with rising fax costs, a firm issued a guideline that transmissions of 10 pages or more should be sent by 2-day mail instead. Exceptions are allowed, but they want the average to be 10 or below. The firm examined 35 randomly chosen fax transmissions during the next year, yielding a sample mean of 14.44 with a standard devi
The accompanying table shows the grades for three randomly selected samples of students in economics, statistics, and accounting classes. Test the hypothesis that the mean grades are the same for all three classes. Use .05 for the level of significance. Economics(X1 ) Statistics(X2 ) Accounting(X3 ) 80 100 95 90 90 90 70 90 88 1
Independent random samples were taken from normal distributions of the yearly production of ships built by the International Ship Building Company under (1) a fixed-position layout and (2) a project layout. The results are given in the accompanying table. Test the null hypothesis that the variance for the fixed-position layout i
Coffee Times weekly advertising expenditure, Coffee Times weekly advertising expenditure (lagged), Coffee Times price index, Coffee Times price index (Lagged), and Estimate on Quick brews weekly advertising expenditure (lagged). The equation we have developed to predict effects on revenue when one or more of the independent va
1) Evolutionary theories often emphasize that humans have adapted to their physical environment. One such theory hypothesizes that people should spontaneously follow a ... 2) Twenty students randomly assigned to an experimental group receive an instructional program; 30 in a control group do not. After 6 months, both groups a
A coin was flipped 60 times and came up heads 38 times. (a) At the .10 level of significance, is the coin biased toward heads? Show your decision rule and calculations. (b) Calculate a p-value and interpret it.
An auditor reviewed 25 oral surgery insurance claims from a particular surgical office, determining that the mean out-of-pocket patient billing above the reimbursed amount was $275.66 with a standard deviation of $78.11. (a) At the 5 percent level of significance, does this sample prove a violation of the guideline that the av
The Web-based company Oh Baby! Gifts has a goal of processing 95 percent of its orders on the same day they are received. If 485 out of the next 500 orders are processed on the same day, would this prove that they are exceeding their goal, using α = .025?