## MATH 399N Week 8 MyStatLab Final Exam Review

##### MATH 399N Hypothesis Testing and Final Review

##### MATH 399N Week 8 MyStatLab Final Exam Review

**1. Question.** Determine if each of the following represents nominal, ordinal, interval, or ratio data.

**2. Question.** The following numbers represent the weights in pounds of six 7- year old children in Mrs. Jones’ 2nd grade class…{25, 60, 51, 47, 49, 45}….Find the mean; median; mode; range; variance; standard deviation.

**3. Question**. If the variance is 846, what is the standard deviation?

**4. Question.** If we have the following data…34, 38, 22, 21, 29, 37, 40, 41, 22, 20, 49, 47, 20, 31, 34, 66…Draw a stem and leaf. Discuss the shape of the distribution.

**5. Question.** What type of sampling technique is (a) a wheat field is divided into sections and a random sample of stocks are taken from each section, and (b) a manufacturer measures every 80th bottle to test for quality?

**6. Question.** If a data set with a normal distribution has a mean of 32 and a standard deviation of 4.9, what percent of the data would you expect to find between 27.1 and 36.9? What range encompasses 99.7% of these data?

**7. Question.** Determine the regression equation for the following data:

**8. Question.** If the correlation coefficient is -.749, what would be the value of the coefficient of determination?

**9. Question.** To predict the annual rice yield in pounds we use the equation…yˆ = 859 + 5.76×1 + 3.82×2 , where x1 represents the number of acres planted and where x2 represents the number of acres harvested and where r2 = .94.

a) Predict the annual yield when 3200 acres are planted and 3000 are harvested.

b) Interpret the results of this r2 value.

**10. Question.** The Student Services office did a survey of 500 students in which they asked if the student is part-time or full-time. Another question asked whether the student was a transfer student. The results follow.

Transfer Non-Transfer Row Totals

Part-Time 100 110 210

Full-Time 170 120 290

Totals 270 230 500

## STATUS

**11. Question.** A shipment of 40 television sets contains 3 defective units. How many ways can a vending company can buy five of these units and receive no defective units?

**12. Question.** In the US, 28% of people consider snickerdoodle as their favorite cookie. You asked 5 people if their favorite cookie was snickerdoodle. Create the probability distribution for the possible outcomes.

**13. Question.** The random variable X represents the annual salaries in dollars of a group of teachers. Find the expected value E(X).

X = {$35,000; $45,000; $55,000} where,

P(35,000) = .4; P(45,000) = .3; P(55,000) = .3.

**14. Question.** An advertising agency is hired to introduce a new product. The agency claims that after its campaign 61% of all consumers are familiar with the product. We ask 7 randomly selected customers whether or not they are familiar with the product. (a) find the probability that, out of 7 customers, exactly 4 are familiar with the product; (b) find the probability that at least 3 customers are familiar with the product; and (c) find the probability that at most 5 are familiar with the product.

**15. Question.** The mean number of cars per minute going through the Eisenhower turnpike automatic toll is about 7. Find the probability that exactly 3 will go through in a given minute.

**16. Question.** Label the following as continuous or discrete distributions.

**17. Question.** On a dry surface, the braking distance (in meters) of a certain car is a normal distribution with µ = 45.1 m and σ = 0.5

**18. Question.** A drug manufacturer wants to estimate the mean heart rate for patients with a certain heart condition. The manufacturer finds 62 people with the condition. From this sample, the mean heart rate is 101 beats per minute with a standard deviation of 8.

**19. Question.** Determine the minimum required sample size if you want to be

80% confident that the sample mean is within 2 units of the population mean given sigma = 9.4. Assume the population is normally distributed.

**20. Question.** A social service worker wants to estimate the true proportion of pregnant teenagers who miss at least one day of school per week on average. The social worker wants to be within 5% of the true proportion when using a 90% confidence interval. A previous study estimated the population proportion at 0.21.

**21. Question.** A restaurant claims that its speed of service time is less than 15 minutes. A random selection of 49 service times was collected, and their mean was calculated to be 14.5 minutes. Their standard deviation is 2.7 minutes. Is there enough evidence to support the claim at alpha = .07. Perform an appropriate hypothesis test, showing each important step. (Note: 1st Step: Write Ho and Ha; 2nd Step: Determine Rejection Region; etc.)