HW #24
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Make Predictions
For Exercise 1–4, use the table and the followinginformation. A survey of students’ favorite sportswas taken from a random sample of students ina school. The results are shown in the table.
1.What is the size of the sample?
2.What is the probability that a student will prefer soccer?
3.What is the probability that a student will prefer volleyball?
4.There are 550 students in the school. Predict how many students at the school prefertrack and field.
Use the percent equation to help you solve.
5.GARDENING A survey showed that 74% of a nursery’s mail-order customers spent morethan $100 on plants each spring. Predict how many of 125,000 mail-order customerswill spend less than $100 on plants next spring.
6.SAVING MONEY A survey of high school students with jobs asked whether the studentssaved some of the money they earned. 82% of the students said they saved some money. Out of 340 students, predict how many would save some of their earnings.
7. TRAVEL COMPANY CUSTOMERS A survey showed that 55% of a travel company’scustomers were planning an overseas vacation the following year. Predict how many ofthe travel company’s 12,400 travelers will vacation overseas the following year.
Unbiased and Biased Samples
Determine if each conclusion is valid. Justify your answer.
1.To determine the most common injury cared for in an emergency room, a reporter goesto the same hospital every afternoon for one month during the summer and observespeople entering the emergency room. She concludes that second degree sunburn is themost common injury.
2.To evaluate customer satisfaction, a grocery store gives double coupons to anyone whocompletes a survey as they enter the store. The store manager determines thatcustomers are very satisfied with their shopping experience in his store.
3.To evaluate the integrity of underground water lines, the department of public worksrandomly selects 20 sites in the city to unearth and observe the water lines. At 5 of thesites, the water lines needed repair. The department of public works concludes thatabout one-fourth of underground water lines throughout the city need repair.
4.DOWNLOADS A guidance counselor asked students who owned mobile phones, which was thelast type of download each one downloaded to theirmobile phone. The results are shown in the table.If there are 420 students in the school, how manycan be expected to download ringtones?
5. DENTISTRY A survey is to be conducted to determine the reasons dental patients arehesitant to go to the dentist. Describe the sample and explain why each samplingmethod might not be valid.
a. Adults that are randomly selected from an office complex are asked to go online and fill out a questionnaire.
b. A randomly selected dentist asks his patients why they may be hesitant to go to adentist.
c. Randomly selected dental patients who are having a routine check-up are asked to write down their feelings.
Misleading Graphs and Statistics
1.Here are the heights, in meters, that 10 men jumped in a high jump competition.
2.19 2.23 2.23 2.23 2.26 2.28 2.29 2.29 2.31 2.33
For these heights, find the mean, median, mode, and range.
In a high jump competition for women, the heights, in meters, that 10 women jumped were recorded.
For these heights the mean was 1.95 m and the range was 0.18 m
Compare the heights that the men jumped with the heights that the women jumped.
2.Cal watched 20 cars go onto a ferry.He counted the number of people in each car.
Here are his results.
1 3 3 4 1 2 2 3 5 4
2 2 4 5 1 3 2 2 3 2
Complete the frequency table.
Number of people in a car / Tally / Frequency1
2
3
4
5
What is the median and mode?
3.Fiona counted the number of cars going onto 6 ferries.Here are her results.
20 18 23 17 15 21
Calculate the mean number of cars.
4.James has three cards.Each card has a number on it.The numbers are hidden.
? / ? / ?The mode of the three numbers is 4.The mean of the three numbers is 5
Work out the three numbers on the cards.
5.Kaz rolled a dice 10 times.
Here are her scores.
2 6 5 4 4 2 1 3 4 3
Find the mean, median, mode, and range.
6.The table shows the midday temperature on each day for ten days.
Day / 1 / 2 / 3 / 4 / 5 / 6 / 7 / 8 / 9 / 10Temperature (C) / 13 / 14 / 12 / 10 / 13 / 16 / 14 / 13 / 18 / 16
Find the range of temperatures.Work out the mean temperature
ANTIQUES For Exercises 7-9, use the table.
7.Find the mean, median, and mode of the data.
8.Which measure might be misleading in describingthe value of each item? Explain.
9.Which measure would best describe the value of each item? Explain.
10.BODY TEMPERATURE The graphs below show the hourly body temperature for a hospitalpatient. Which graph would be more helpful to the doctor in showing the change inbody temperature? Explain.
Mean Absolute Deviation
1.BASEBALL The top five salaries and the bottom five salariesfor the 2010 New York Yankees are shown in the table below.Salaries are in millions of dollars and are rounded to the nearesthundredth.
- Find the mean absolute deviation for each set of data. Roundto the nearest hundredth.
Top Five SalariesBottom Five Salaries
- Write a few sentences comparing their variation.
2. Find the mean absolute deviation for each set of data. Round to the nearesthundredth if necessary. Then describe what the mean absolute deviationrepresents.
a.
b.
3. FUNDRAISING Thetable shows the amount of money raised by thehomerooms for two grade levels at a middle school. Find the meanabsolute deviation for each set of data. Round to the nearest hundredth.Then write a few sentences comparing their variation.
4-7. POPULATION For Exercises 4-7, refer to the tablethat shows the recent population, in millions, of theten largest U.S. cities.
4. Find the mean absolute deviation. Round to thenearest hundredth.
5. How many data values are closer than one mean absolute deviationaway from the mean?
6. Which population is farthest from the mean? How far away from themean is that population? Round to the nearest hundredth.
7. Are there any populations that are more than twice the mean absolutedeviation from the mean? Explain.
VOCABULARY For Exercises 8 and 9, look up the word deviate in adictionary or online.
8. What does the word deviate mean? How can it help you remember whatthe mean absolute deviation refers to?
9. How does the word absolute help you to remember how to calculate themean absolute deviation?