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If x1 and x2 are normally distributed random variables with a mean of 95 and a standard deviation of 20, and that x1 and x2 are independent of each other, then P(x1 and x2 < 60) is:
A bank's loan officer rates applicants for credit. The ratings are normally distributed with a mean of 200 and a standard deviation of 50. If 40 different applicants are randomly selected, find the
If the z-value for a given value x of the random variable X is z = 1.96, and the distribution of X is normally distributed with a mean of 60 and a standard deviation of 6, to what x-value does this
A researcher tests 10 individuals before and after an experimental procedure.The results are shown below. How many degrees of freedom are there?
Discuss how a t Test for a dependent variable can be of great value in applying a new approach to the treatment of aggressive behavior to a small group of students. Why would this t Test be preferre
The amount of time to complete a particular exam is believed to have a mean of 52 minutes and a standard deviation of 4.8 minutes. A sample of 36 students was selected and their times to finish the
As a sample size approaches infinity, how does the student's t distribution compare to the normal z distribution? When a researcher draws a sample from a normal distribution, what can one conclude a
The central limit theorem can be used to analyze round-off error. Suppose that the round-off error is represented as a uniform random variable on [-1/2, 1/2]. If 100 numbers are added, approximate t
If 200 of the adults surveyed were in the age category of 24 and under and they provided a standard deviation of $14.50, construct a 95% confidence interval for the weekly average expenditure on fas
Carry out a hypothesis test, at 5% significance level, to determine whether the president should retain Supplier A.
The Hawks are currently winning 0.55 of their games. There are 5 games in the next two weeks. What is the probability that they will win more games than they lose?
Question: Use the program Binomial Probabilities to find the probability that, in 100 tosses of a fair coin, the number of heads that turns up lies between 35 and 65, between 40 and 60, and between
If the spinner lands on on any space not chosen, the player loses the $2.00. (Assume that landing on a line is voided and spinner is respun) What is the expected value of the game?
Question: A particular firm carried out an extensive study into the costing of a specific type of project. it was found that the probability of completing such projects to budget is 0.2.
A bag contains 10 red, 12 green, and 8 yellow marbles. Assuming that all the marbles are equally likely to be picked from the bag, what is the probability that the second marble is yellow, given tha
Compute a 95% confidence interval for the population mean, based on the sample 1, 2, 3, 4, 5, 6, and 39. Change the number from 39 to 16 and recalculate the confidence interval. Using the results, d
Question: In order to determine an interval for the mean of a population with unknown standard deviation a sample of 61 items is selected. The mean of the sample is determined to be 23. The number o
Question: A population has a standard deviation of 50. A random sample of 100 items from this population is selected. The sample mean is determined to be 600. At 95% confidence, the margin of error
Two hundred students are enrolled in an Economics class. After the first examination, a random sample of 6 papers was selected. The grades were 65, 75, 89, 71, 70 and 80. Determine the standard erro
He neglected to report what confidence coefficient he had used. Based on the above information, determine the confidence coefficient that was used. Assume the population has a normal distribution.
The average monthly electric bill of a random sample of 256 residents of a city is $90 with a standard deviation of $24. Construct a 90% confidence interval for the mean monthly electric bills of all
Predict the average weekly sales of pet food for stores with 20 feet of shelf space for pet food. Compute coefficient of correlation. Compute standard error of estimate.
Change the number from 39 to 16 and recalculate the confidence interval. Using the results, describe the effect of an outlier or extreme value on the confidence interval.
In order to determine an interval for the mean of a population with unknown standard deviation a sample of 61 items is selected. The mean of the sample is determined to be 23. The number of degrees
A population has a standard deviation of 50. A random sample of 100 items from this population is selected. The sample mean is determined to be 600. At 95% confidence, the margin of error is: