K310- Ch 3 Statistics HW Review
A random sample of 10 subjects have weights with a standard deviation of 12.0327 kg. What is the variance of their weights? Be sure to include the appropriate units with the result.
144.7859 kg2
One common system for computing a grade point average (GPA) assigns 4 points to an A, 3 points to a B, 2 points to a C, 1 point to a D, and 0 points to an F. What is the GPA of a student who gets an A in a 3-credit course, a B in each of two 4-credit courses, a C in a 3-credit course, and a D in a 4-credit course?
2.6
Which of the following is NOT a characteristic of the mean?
The mean is called the average by statisticians.
Which of the following is NOT a value in the 5-number summary?
mean
In modified boxplots, a data value is a(n) _______ if it is above Q3+(1.5)(IQR) or below Q1−(1.5)(IQR).
outlier
The Range Rule of Thumb roughly estimates the standard deviation of a data set as _______.
s = range / 4
A data value is considered _______ if its z-score is less than −2 or greater than 2.
significantly low or significantly high
For data sets having a distribution that is approximately bell-shaped, _______ states that about 68% of all data values fall within one standard deviation from the mean.
the Empirical rule
Whenever a data value is less than the mean, _______.
the corresponding z-score is negative
A defunct website listed the "average" annual income for Florida as $35,031. What is the role of the term average in statistics? Should another term be used in place of average?
The term average is not used in statistics. The term mean should be used for the result obtained by adding all of the sample values and dividing by the total number of sample values.
Identify the symbols used for each of the following: (a) sample standard deviation; (b) population standard deviation; (c) sample variance; (d) population variance.
a. The symbol for sample standard deviation is s. b. The symbol for population standard deviation is σ. c. The symbol for sample variance is s2. d. The symbol for population variance is σ2.
The square of the standard deviation is called the _______.
variance
When a data value is converted to a standardized scale representing the number of standard deviations the data value lies from the mean, we call the new value a _______.
z-score
A magazine published a list consisting of the state tax on each gallon of gas. If we add the 50 state tax amounts and then divide by 50, we get 27.3 cents. Is the value of 27.3 cents the mean amount of state sales tax paid by all U.S. drivers? Why or why not?
No, the value of 27.3 cents is not the mean because the 50 amounts are all weighted equally in the calculation, but some states consume more gas than others, so the mean amount of state sales tax should be calculated using a weighted mean.
