Download Name: Statistics Chapter 3 Quiz 1 – Measures of Central Tendency

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Statistics
Chapter 3 Quiz 1 – Measures of Central Tendency and Measures of Variation
Determine whether each statement is true or false. If the statement is false, explain why.
1.
When the mean is computed for individual data, all values in the data set are used.
2. The mean cannot be found for grouped data when there is an open class.
3. One-half of all the data values will fall above the mode, and one-half will fall below the mode.
4. A single, extremely large value can affect the median more than the mean.
5. In a data set, the mode will always be unique.
6. One disadvantage of the median is that it is not unique.
7. The mode and midrange are both measures of variation.
8. The range and midrange are both measures of variation.
Select the best answer.
9.
What is the value of the mode when all values in the data set are different?
a. 0
b. 1
c. There is no mode
d. It cannot be determined unless the data values are given.
10. When data are categorized as, for example, places of residence (rural, suburban, urban), the most appropriate
measure of central tendency is:
a. Mean b. Median
c. Mode
d. Midrange
Complete the statements with the best answer.
11. A measure obtained from sample data is called a(n) ________________________________.
12. Gnerally, Greek letters are used to represent __________________, and Roman letters are used to represent
____________________________.
13. The positive square root of the variance is called the _____________________.
14. The symbol for the population standard deviation is ______________________.
15. When the sum of the lowest data vlaue and the highest data value is divided by 2, the meaures is called
_____________________.
16. If the mode is to the left of the meidan and the mean is to the right of the median, then the dsitribution is
___________ skewed.
17. An extremely high or extremely low data value is called a(n) _______________________________.
Calculation
18. The number of highway miles per gallon of the 10 worst vehicles is shown.
12
15
13
14
15
16
17
16
17
18
Find each of these.
a. Mean
b. Median
c. Mode
d. Midrange
e. Range
f.
Variance
g. Standard deviation
19. The distribution of the number of errors that 10 students made on a typing test is shown.
Errors
Frequency
0-2
1
3-5
3
6-8
4
9-11
1
12-14
1
Find each of these
a. Mean
b. Modal class
c. Variance
d. Standard Deviation
20. In a survey of third-grade students, this distribution was obtained for the number of “best friends” each had.
Number of students Number of best friends
8
1
6
2
5
3
3
0
Find the avearge number of best friends for the class. Use the weighted eman.
21. A survey of grocery stores showed that the average number of brands of toothpaste carried was 16, with a
standard deviation of 5. The same survey showed the avearge length of the time each store was 7 years, with a
standard deviation of 1.6 years. Which is more variable, the number of brands or the number of years?
22. The average national SAT score is 1019 (verbal and math). If we assume a bell-shaped distribution and a
standard deviation equal to 10, what percentage of scores will you expect to fall between 909 and 1129?