# Stats Final guide

**Topics:**Arithmetic mean, Normal distribution, Statistical hypothesis testing

**Pages:**13 (3002 words)

**Published:**March 31, 2014

(1) A study of the number of cars sold looked at the number of cars sold at 500 Dealers The smallest dealer had 11 cars sold and the largest had 154 cars sold. If you were going to create a frequency distribution of the number of cars sold using six classes in your frequency distribution, which of the following might be a reasonable first class?

(a) 0 to 25

_ (2) Give that a sample of 25 had x = 75, and (x-x)² = 48 the mean and standard deviation are

_ (c) X = 3.0 and S = 48/24

(3) Which of the following is always true for a test of a hypothesis? (a) The type ll error is more important than type l error (b) is larger then (c ) is the probability of a type ll error (d) A type l error occurs when you accept the null hypothesis when it is not true (e) None of the above is true.

(4) Suppose that, in attesting situation with a population that is normally distributed, The null hypothesis is that the population mean is equal to 41. A sample of size 36 had a sample mean of 41 and sample standard deviation of 2. Which of the following is correct?

(b) You cannot reject the null hypothesis

(5) If you take a sample of size 24 from a normal population for which you do not know the population standard deviation and want to calculate a 95% confidence interval for the mean, which is not need?

(c) The value of Z0.025

(6) The coefficient of determination, R²

(b) Tell us how close the Regression line fits the points in a scatter diagram.

(7) The expected value of a random variable is also-- E(X)

(c) A weighted average

(8) The retail price of a product is $5 per unit & the cost of production is $2 per unit. If the expected number of unit sold is 4, the expected profit will be (b) 12

(9) Is not assumption that is required for the use of binomial formula? (a) The trails are independent (b) The probability of success is the same for ever trail. (c) Each trail has only 2 possible outcomes (d) The random variable is the number of successes out of a trails (e) All of the above.

(10) You are measuring the life time of a light bulb. Which of the following might be the distribution of this random variable

(a) Binomial (b) Normal (c) Poisson (d) All three (e) None

(11) If the P value is less then , you

(c ) Should reject the null hypothesis.

(12) Because of the variation in the measured contents of a can of cola, (b) The average contents of a sample of 10 cans will give us the average contents for the day’s production of 100,000 cans.

(13) A manufacturer of children’s toy claims that exactly 5% of all his products are defective. When 500 toys from today’s output were examined, 8% were found to be defective. What is the parameter?

(b) The % of all the toys made that are defective.

(14) X claims that the average box of X contains 12 ounces. You bought 1 box at each 5 different grocery stores. The weights were 13.1, 11.6, 12.1, 12.3 & 11.9 ounces. The mean weight of the 5 boxes was 12.2 ounces. The sample is -- (5) (e) None of the above.

(15) A car manufacturer is studying the relationship between the weight of its vehicles and the mileage they get in city driving. Which following would an analyst for the company construct to aid in this study?

(b) The least squares regression line.

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(16) Which of the following is NOT quantitative date?

(c ) Whether a driver buys premium gasoline or not

(17) A basketball player scored 12, 25, 16, & 13 points in her last 4 games. What is the mean number of points per game she...

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