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For the chi-square hypothesis tests, however, the degrees of freedom are based on the numbers of categories, or cells, in which participants can be counted.
Assuming that the data are normally distributed with a mean of 25 and a standard deviation of 1.25, what is the z-score for a value of 27?
What are the hypotheses when conducting the chi-square test for goodness-of-fit?
The lengths of pregnancies of humans are normally distributed with a mean of 268 days and a standard deviation of 15 days. A baby is premature if it is born three weeks early.
The chi-square test for goodness-of-fit is a nonparametric hypothesis test used with one nominal variable. The chi-square test for independence is a nonparametric test used with two nominal variable
In a survey of 2480 golfers, 15% said they were left-handed. The survey's margin of error was 3%. Construct a confidence interval for the proportion of left-handed golfers.
A sample of 3 items is selected at random from a box containing twenty items of which 4 are defective. The expected value of defective items E[X] in the sample is 3/5. The question is what is E[X2]
Suppose it is known that 10% of people who play poker machines have a gambling problem. Suppose it is also known that 20% of the population play poker machines and 5% of the population have a gambli
The Australian newspaper is read by 70% of Coalition voters, 35% of ALP voters, and 20% of Greens voters. If a randomly selected person is observed reading The Australian, what is the probability th
If one person is selected at random from the group, what is the probability that the person answered "yes" or was male?
Research suggests that reaction time for an in-traffic response to a brake signal from standard brake lights can be modelled with a normal distribution having a mean of 1.24 seconds and a standard
The density function of a continuous random variable X, the total number of hours, in units of 100 hours, that a family runs a vacuum cleaner over a period of one year is described by the following
If a sample of 36 workers is chosen, what is the probability that the sample mean of their weights is between 163 and 170?
Assuming that the population standard deviation is known to be 1.6 cm, use a 0.05 significance level to test the claim that the mean circumference of all pumpkins is equal to 39.9 cm.
A simple random sample of 144 observations will be taken. What is the probability that the sample mean will be between 297 and 303?
A fast-food restaurant sells hamburgers and chicken sandwiches. On a typical weekday, the demand for hamburgers is normally distributed with a mean 313 and a standard deviation 57; the demand for ch
Find the probabilities for the following discrete random variables a. Among a shipment of 5,000 tires, 1,000 are slightly blemished. If one purchases 10 of these tires, what is the probability that
A production process produces 90% non-defective parts. A sample of 10 parts from the production process is selected. What is the probability that the sample will contain 7 non-defective parts?
Suppose a random sample of 8 stores, from which merchandise has been stolen, is chosen. _________Find the mean µ of this probability distribution.
What is the expected number of shoppers that will buy the item if a random sample of 50 shoppers taste a free sample?
Plot the data, fit a trend line, and discuss the strength of the regression model. In addition, explore a quadratic trend and compare the results of the two models.
For a medical study, a researcher wishes to select people in the middle 60% of the populartion based on blood pressure. The mean is 120 and standard deviation is 8. Find the upper and lower readi
Is there sufficient evidence to support the claim that there is a linear correlation between hours of preparation and test score.
The value of the linear correlation coefficient was found to be 0.885. Based on this data is there a linear relationship between the two?
A committee of 3 people is formed from 6 women and 4 men. What is the cumulative probability function for the number of men selected?