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A laboratory testing of five samples on the content of a certain water-quality indicator results in the following values: 3.41, 3.06, 2.94, 3.27, and 3.32 mg/L
Ten random measurements in parking lots A and B yield readings with standard deviations of 12 and 9, respectively. Can manufacturer B legitimately claim to provide more uniform lighting?
Researchers studied the effects of adding an exercise program to dieting in the achievement of weight loss. A sample of 45 men ages 18-20 (Group 1) were observed for weight loss using a diet only, a
A researcher wishes to test the hypothesis that the mean age at first marriage for women in Texas is less than 24. In a sample of 56 Texas women, he finds that the average age is 25.4 with a standar
You have many cans of food to organize on a shelf in your pantry. You have 3 cans of soup, 4 cans of beans ,and 5 cans of tomato sauce. Assume that the cans of each type differ in variety . (for exa
Write out the null and the alternative hypothesis. What is the appropriate data analysis method for this study? Calculate the test statistic and effect size. Make the decision, and explain why.
In a normal distribution, what z-score value separates the highest 40% of the scores from the rest of the distribution?
A high school math teacher gave her 30 students a math exam. In this exam, the average scores for the high school students in the United States is 48.00. If she sets the significant level as 0.05, a
Suppose that the weight of a large bag of sugar is N(5.05, 0.081), and that the weight of a small bag of sugar is N(1.01,0.025). Find the probability that five small bags are heavier than one large
Suppose that the number of accidents at a nuclear power plant in one week has a Poisson distribution with mean 3, and suppose that the number of accidents in one week is independent of the number in
Two draws will be made at random from a box containing 5 marbles, red, yellow, green, black and blue. The unconditional probability of getting a red marble on the first draw is 1/ 5 . The unconditio
Suppose that a device stops working if one of its five components fails, and suppose that the lifetimes of the five components are exponentially distributed with means 10000,15000,20000,25000,and 50
Suppose it has been observed that touchdowns scored in a game by your favorite football team are Poisson random variables. The rate is .. = 4 per game. We know from the lecture that the time until t
A roulette wheel has 38 slots in which the ball can land. Two of the slots are green, 18 are red, and 18 are black. The ball is equally likely to land in any slot. The roulette wheel is going to be
Your manager, who just read an abridged version of a statistics book, wants you to test hypotheses for the difference in two population means. The sample sizes for each are 23.
One ecologist argues that the island does not increase retention time because the travel velocity is increased along with travel length. Dye studies are used to measure retention time in 5 wetlands
The total expenses of a hospital are related to many factors. Two of these factors are the number of beds in the hospital and the number of admissions. Data were collected on 14 hospitals, as shown
A physics lab instructor wants to estimate the time required for physic students to complete a required experiment. From a previous study she found the population standard deviation to be 16 min. Ho
A college requires an IQ of 120 or more for entrance. From what percentage of the population must it draw its students? Mean is 100 and standard deviation is 15
A random sample of 10 has a mean of 110. Test the null hypothesis that µ = 120 against the alternative hypothesis that µ < 120 at the 5% level of significance for the following cases
If no preliminary sample is taken to estimate p, how large a sample is necessary to be 90% sure that a point estimate will be within a distance of .06 from p?
It is desired to estimate the mean time of continuous use until a wireless router will first required service. If it can be assumed that the standard deviation is 60 days,
Some plastic rods are automatically cut into lengths of 6 in. Actual lengths are normally distributed about a mean of 6 in and their standard deviation is .06 inches. What proportion of the rods exc