Stats Unit 2
A value at the center or middle of a data set is a(n) _______.
measure of center
5-number summary
min, Q1, median, Q3, max
The measure of center that is the value that occurs with the greatest frequency is the _______.
mode
"At least one" is equivalent to _______.
"one or more"
A Social Security number consists of nine digits in a particular order, and repetition of digits is allowed. After seeing the last four digits printed on a receipt, if you randomly select the other digits, what is the probability of getting the correct Social Security number of the person who was given the receipt?
1/100,000
If the standard deviation for a set of data is 0, which of the following must be true?
All of the data values are identical
Which of the following is always true? -The mean and median should be used to identify the shape of the distribution. -In a symmetric and bell-shaped distribution, the mean, median, and mode are the same -For skewed data, the mode is farther out in the longer tail than the median -Data skewed to the right have a longer left tail than right tail
In a symmetric and bell-shaped distribution, the mean, median, and mode are the same
Which of the following is NOT a value in the 5-number summary? -Q1 -Min -Mean -Median
Mean
When randomly selecting an adult, A denotes the event of selecting someone with blue eyes. What do P(A) and P(Ā) represent?
P(A) represents the probability of selecting an adult with blue eyes. P(Ā) represents the probability of selecting an adult who does not have blue eyes.
What does P(B|A) represent?
The probability of event B occurring after it is assumed that event A has already occurred.
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.
If radio station call letters must begin with either K or W and must include either two or three additional letters, how many different possibilities are there?
There are 36504 different possibilities.
Two events A and B are _______ if the occurrence of one does not affect the probability of the occurrence of the other.
independent
When using the ____, always be careful to avoid double-counting outcomes.
addition rule
Which of the following is NOT a measure of center? -mean -mode -census -median
census
A _______ probability of an event is a probability obtained with knowledge that some other event has already occurred.
conditional
Methods used that summarize or describe characteristics of data are called _______ statistics.
descriptive
Events that are _______ cannot occur at the same time.
disjoint
(grams)The unit for population standard deviation would be
g
If sample data consist of weights measured in grams, then correctly complete the following sentences... The unit for sample standard deviation would be
g
(grams)The unit for population variance would be
g^2
(grams)The unit for sample variance would be
g^2
The symbol for sample standard deviation
s
The Range Rule of Thumb roughly estimates the standard deviation of a data set as
s= range/4
The symbol for sample variance
s^2
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
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
The symbol for population standard deviation
σ
The symbol for population variance
σ^2
