Week 1 New

Re. The evaluated group is a sample because a population is the complete set of people or things being studied, as opposed a sample is a subgroup of a population as it is in this case-500 patients were selected from the population of patients.

b) An investigation of 150 randomly selected local restaurants concluded that 42% of local restaurants have serious health code violations. Is this a population or a sample; explain your answer.

Re. The evaluated group is a sample because a population is the complete set of people or things being studied, as opposed a sample is a subgroup of a population as it is in this case-150 local restaurants were randomly selected from all the local restaurants.

2) Determine whether the given value is a statistic or a parameter.

a) A researcher determines that 42.7% of all downtown office buildings have ventilation problems. Is this a statistic or a parameter; explain your answer.

Re. Population Parameter-

b) After taking the first exam, 15 of the students dropped the class. Is this a statistic or a parameter; explain your answer.

Re. Population Parameter-

3) Identify the type of sampling used.

a) A tax auditor selects every 1000th income tax return that is received. What type of sample is this and why?

Re. Stratified

b) The name of each contestant is written on a separate card, and the cards are placed in a bag with three names being picked from the bag. What type of sample is this and why?

Re. Random

4) Is the study experimental or observation and why?

a) A political pollster reports that his candidate has a 10% lead in the polls with 10% undecided.

Re. Observational

5) Select the study that is most appropriate and EXPLAIN WHY it is most appropriate for the study.

a) Is the aspirin produced by a particular pharmaceutical company better than that of a competitor at relieving headaches? Which of the following would best be used to study this: 1) a case-controlled observation; 2) an observation; 3) a double-blind experimental procedure; and 4) and experimental procedure.

Re. Double-blind experimental procedure

From Chapter One

1) Focus on Public Health—On page 44 of the text, it discusses the Harvard Nurses’ Health Study, which is a very well-known study that has been conducted for a number of years. Answer discussion question two at the end of the article.

Chapter Two

1) Identify the following variables as either qualitative or quantitative and EXPLAIN your answers.

a. The number of people on a jury.

Re. Quantitative

b. The color of your house

Re. Qualitative

2) Identify the number as either continuous or discrete and EXPLAIN your answers.

a. The average height of all freshmen entering college in a certain year is 68.4 inches.

Re. Continuous

b. The number of limbs on a 2-year-old oak tree is 21.

Re. Discrete

3) Determine which of the four levels of measurement is most appropriate and explain your answer.

a. Temperatures in degrees Fahrenheit of the ocean at various depths.

Re. Interval level of measurement because each degree of transformation has an exact meaning.

b. The rank of individuals in the military

Ordinal data because the can be put in an increase or decrease order.

c. The number of people with blue, brown and red hair in a classroom

Re. The ratio level of measurement because there is a true zero.

4) Determine the following (show your work):

a. The speed of a new microprocessor is 800MHZ, but a new test of its speed gives a measurement of 820MHZ. What is the absolute error? What is the relative error?

Re. The absolute error is 800MHZ-820MHZ=20MHZ; the relative error is 20MHZ/820MHZ=0.02439 or 2.44%

b. Convert 1/16 to a percent

Re. 6.25%

c. Convert 0.45 to a percent

Re. 45%

d. Humanities majors spend an average of $115 per course on books. Mathematics majors spend an average of $70 per course on books.

What is the percent difference between the two amounts relative to the amount for mathematics majors (round to the nearest percent)?

Re. The relative change is (70-115)/70= -0.642857 or -64.3% there has been in decrease of 64.3% that the mathematics majors spend on average per course on books.

e. Suppose that the cost of a statistics text was $50 in 1985 and is $100 in 2000. What is the “Statistics Text Index” number, rounded to the nearest tenth, for the 2000 edition with the 1985 price as the reference value?

From Chapter Two

2) Focus on Economics—On page 76 and 77, the article looks at an important issue to everyone—the economy. In particular it is focusing on whether our standard of living is improving. Answer discussion question one at the back of the article.