Exam 1: Introduction to Statistics

A bus company claims that in the past year it has reduced the number of late departures of buses by 100%. What is wrong with this statement?

The four levels of measurement that are commonly used for classifying data are ratio, ________, ________, and ________.

A questionnaire is sent to 10,000 persons. 5,000 responded to the questionnaire. 3,000 of the respondents say that they "love chocolate ice cream". We conclude that 60% of people love chocolate ice cream. What is wrong with this survey?

A ________ is the collection of data from every member of the population.

A stock analyst selects a stock from a group of twenty for investment by choosing the stock with the greatest earnings per share reported for the last quarter.

Identify which of these types of sampling is used: random, stratified, systematic, cluster, convenience. -The name of each contestant is written on a separate card, the cards are placed in a bag, and three names are picked from the bag.

Determine which of the four levels of measurement is most appropriate. Level of satisfaction of survey respondents.

Distinguish between categorical and quantitative data. Give an example of each.

On a test, if 115 questions are answered and 41% of them are correct, what is the number of correct answers?

Would an observational study or an experiment be more appropriate to investigate the effects on fertilizer on plant growth? Explain.

An article stated that last year 807 people taking a certain medication suffered from serious side effects while this year, after the medication had been modified, only 391 suffered serious side effects. What information is missing? Why would it be important to include this information?

Use the data in the table to answer the question. The x-values are amounts of saturated fat (in grams) in various regular two-ounce muffins. The y-values are amounts of saturated fat (in grams) in various "low fat" two-ounce muffins. Amounts of Saturated Fat in Regular and Low-Fat Muffins 3.7 4.9 4.3 6.4 4.2 4.5 1.2 2.1 2.2 1.9 1.4 2.4 Is each x-value matched with a corresponding y-value? That is, is each x-value associated with the corresponding y-value in some meaningful way? If the x- and y-values are not matched, does it make sense to use the difference between each x-value and the y-value that is in the same column?

The number of freshmen entering college in a certain year is 621.

Identify the type of observational study (cross-sectional, retrospective, prospective). -At a school there are two different math classes of the same age. The two classes have different teachers. The school principal is interested in gauging the effectiveness of two different teaching methods and asks each teacher to try one of the methods. At the end of the semester both classes are given the same test and the results are compared. In this experiment, what is the variable of interest? Give some examples of variables which could be confounding variables.

100,000 randomly selected adults were asked whether they drink at least 48 oz of water each day and only 45% said yes.

A doctor induces a cardiac stress test to determine the reason for a patient's illness.

A T.V. show's executives raised the fee for commercials following a report that the show received a "No. 1" rating in a survey of viewers.

Provide an appropriate response. -An electronics store receives a shipment of eight boxes of calculators. Each box contains ten calculators. A quality control inspector chooses a box by putting eight identical slips of paper numbered 1 to 8 into a hat, Mixing thoroughly and then picking a slip at random. He then chooses a calculator at random from the box Selected using a similar method with ten slips of paper in a hat. He repeats the process until he obtains a Sample of 5 calculators for quality control testing. Does this sampling plan result in a random sample? Simple Random sample? Explain.

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

Which of the following is an inappropriate way to deal with missing data?