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A pair of dice is rolled 270 times. using the normal curve approximation, what is the probability that a total of 7 occurs?
Find the joint probability density of the two random variables x and y whose joint distrubution function is given by :
Describe what is meant by a binomial experiment. How do binomial experiments apply to each of the four probability distributions covered in Chapter 3?
Suppose a previous study has shown the sample standard deviation of a particular model of automobile to be 3.12 mpg. How large a sample is necessary to estimate the mean miles per gallon to within 0
A company makes electric motors. The probability an electric motor is defective is 0.01. What is the probability that a sample of 300 electric motors will contain exactly 5 defective motors?
Scores on an endurance test for cardiac patients are normally distributed with mean = 200 and standard deviation = 30.
The average height of a random sample of 2000 women is 64 inches, with a standard deviation of two inches. What probability distribution most likely applies here?
Personnel tests are designed to test a job applicant's cognitive and/or physical abilities. A particular dexterity test is administered nationwide by a private testing service. It is known that for
What is the probability that one random selected will last more than 7 days? What is the prob that the mean lifetime of 5 bouquets will be less than 5 days? As the sample size increases will the stana
What is the x(alpha/2) critical value that wouls be used to create a 97% confidence level for the true proportion of tax returns with serious errors?
A population variance 34. What is the standard deviation ? What if n= 14 what would be the standard deviation of the mean?
As their sample size increases, what's the expected shape of the distribution of amounts purchased in the sample? As the sample size increases, what's the expected shape of the sampling model for the
Suppose a highlighter manufacturer wanted to find out whether a highlighter lasted longer than the claim of 14 continuous hours. They tested 40 highlighters and recorded the number of continuous hou
A researcher was interested in determining the effect of an experimental drug on the lifespan of laboratory rats. Shown below is a summary of lifespans, in months, for laboratory animals administ
Why does analysis of variance should be conducted only when population variances can be assumed to be equal? why not when they are approximately equal? Is it because there is no way of knowing the
A sample of 250 observations is selected from a normal population for which the population standard deviation is known to be 24. The sample mean is 20.
The power generated by a solar electric generator is normally distributed with mean 15.6 kilowatts and standard deviation of 4.1 kilowatts. We may be 95% sure that the generator will deliver at leas
The time interval between two successive customers entering a store in a mall is exponentially distributed with a mean of 6.55 seconds. What is the probability that the time interval is more than 10
When running a non-parametric test on SPSS with a small sample size, which test statistic will NOT provide the most accurate result?
A simple random sample of 40 items resulted in a sample mean of 25. The population standard deviation is 5. What is the standard error of the mean (to 2 decimals)?
Using a table of critical t-values of the t distribution, find the range of values for the P-value for testing a claim about the mean body temperature of healthy adults for a left-tailed test with n
The results of a Newsweek poll concerning views on abortion showed that of n = 1002 adults, 39% favored the right-to-life stand while 53% were pro-choice. The poll reported a margin of error of plus
State University uses thousands of fluorescent light bulbs each year. The brand of bulb it currently uses has a mean life of 760 hours. A competitor claims that its bulbs, which cost the same as the
However, the Creel Survey reported that of a random sample of 51 fish caught, the mean length was x-bar = 18.5 inches, with estimated standard deviation s = 3.2 inches. Do these data indicate that t
Acid rain, caused by the reaction of certain air pollutants with rainwater, appears to be a growing problem in the northeastern United States. Acid rain affects the soil and causes corrosion on expo