Instructions:

1.Answers should be in Hand-Written. Submit only answer sheets.

2.This assignment is to be completed independently.

3.Show all work / steps for full credit (including writing the Formulas)

4.Be neat and organized!! If I cannot read your work, I cannot give you credit

5.Submit your answer sheets on Moodle in one file (pdf or word), image file will not be accepted

Every semester I teach this class, there are a few people who get

a zero F because of this.Do not let this be you!

Q1) We collect these data from 50 male students. Which variable is qualitative (categorical) and which is quantitative?

a. eye color

b. head circumference

c. marital status

d. number of cigarettes smoked daily

e. number of TV sets at home

f. temperatures in Southern California for the past year

g. weather conditions in Southern California in past year

Q2) The General Social Survey asked the question, "After an average workday, about how many hours do you have to relax or pursue activities that you enjoy?" to a random sample of 1,155 Americans. The average relaxing time was found to be 1.65 hours. Determine which of the following is an observation, a variable, a sample statistic (value calculated based on the observed sample), or a population parameter.

(a) An American in the sample.

(b) Number of hours spent relaxing after an average workday.

(c) 1.65.

(d) Average number of hours all Americans spend relaxing after an average workday.

Q3) Determine the type of sampling used (simple random, stratified, systematic, cluster, or convenience).

a)A soccer coach selects 6 players from a group of boys aged 8 to 10, 7 players from a group of boys aged 11 to 12, and 3 players from a group of boys aged 13 to 14 to form a recreational soccer team.

b)A pollster interviews all human resource personnel in five different high tech companies.

Q4) Identify the following research studies as observational or a controlled experiment. Explain why.

a)A study conducted at Virginia Polytechnic Institute and presented by Psychology Today divided female athletes into two groups and had the students perform as many sit-ups as possible in 90 seconds. The first group was told only to 'do your best,' while the second group was told to try to increase the number of sit-ups they did each day by 10%. After 4 days, the first group averaged 43 sit-ups while the second group averaged 56 sit-ups. The conclusion was that athletes who were given specific goals performed better than those who were not given specific goals.

b)Data from the Motorcycle Industry Council stated that "Motorcycle owners are getting older and richer." Data were collected on the ages and incomes of motorcycle owners for the years 1980 and 1998 and then compared. The findings showed considerable differences in the ages and incomes of motorcycle owners for the two years.

Q5) The mean and median scores of a recent Stat 111 exam were close to 68%. The instructor decided not to count one score of zero that was from an absent student to get a better representation of the class average and then recalculated the new mean and median.

a)Will the new mean increase, decrease or remain about the same? Explain.

b)Will the new median increase, decrease or remain about the same? Explain.

c)Will the overall range increase, decrease or remain about the same? Explain.

d)Will the IQR increase, decrease or remain about the same? Explain.

Q6) In a survey collecting data about the salaries earned by recent college graduates, Li found that her salary was in the 78th percentile. Should Li be pleased or upset by this result? Explain.

Q7)

a)Commuting times for employees of a local company have a mean of 63.6 minutes and a standard deviation of 2.5 minutes. What does Chebyshevs Theorem say about the percentage of employees with commuting times between 56.1 minutes and 71.1 minutes?

b)A small computing center has found that the number of jobs submitted per day to its computers has a distribution that is approximately bell shaped, with a mean of 75 jobs and a standard deviation of 8. Where do we expect most (approximately 95%) of the distribution to fall?

Q8) Here is a histogram of the Distribution of grades on a quiz

a)How many students took the quiz?

b)What percentage of students scored below a 60 on the quiz? (Assume left-hand endpoints are included in each bin.)

Can we answer to questions below using the histogram? Choose "yes" if the histogram provides information needed to answer the question.

a)What is the lowest grade on the quiz?

b)What percentage of the students scored between 75 and 80?

c)What percentage of the students made an A on the quiz if an A is 90 or better?

d)How many students fail the quiz if s score below 70 is considered failing?

e)What was the most common score on the quiz?

Q9) The boxplot to the right displays ratings for TV shows during sweeps week. Answer the following questions.

a)What is the percentage of Shows that have a rating of less than 20?

b)What is the percentage of Shows that have a rating of greater than 14?

c)Within which interval of rating would you expect to find the largest number of shows?

Q10) A male student of the author has a measured pulse rate of 52 beats per minute. According to a National Center for Health Statistics data set, males have a mean pulse rate of 67.3 beats per minute and a standard deviation of 10.3 beats per minute. Determine whether the student's pulse rate is significantly low or high by calculating the z score. Consider usual pulse rates to be within 2 standard deviations of the mean. Justify your answer.