Exam 1 Study questions Flashcards
(104 cards)
1
Q
Range
A
The difference between the highest and lowest value
2
Q
Variance measures the variation in the data set, namely, how far away the data points deviate away from the center
A
TRUE
3
Q
A sample is a subset of the population (T/F)
A
TRUE
4
Q
Which of the following variable(s) is (are) quantitative? Select all that apply.
A
Body Weight, Time
5
Q
When the population is small and all elements can be measured, which type of statistics is more appropriate?
A
Descriptive Statistics
6
Q
When a population is large and we can only afford to measure a sample of elements, which type of statistics has to be used in order to make inference about the population from the sample?
A
Statistical Inference
7
Q
During the random sampling, if we put the sampled element back to the population before the next sampling, It is called
A
Sample with replacement
8
Q
Bar Chart and Pie Chart are used for display __________data?
A
qualitative
9
Q
A data set that records the hair color of a sample is a qualitative data. (T/F)
A
TRUE
10
Q
A data set that stores individuals’ height is a qualitative data. (T/F)
A
FALSE
11
Q
Which one can be used to graphically describe quantitative data?
A
Histogram
12
Q
Which one below is quantitative?
A
Height
13
Q
Frequency polygon is graphed based on bar chart. (T/F)
A
FALSE
14
Q
Frequency polygon is graphed based on histograms. (T/F)
A
TRUE
15
Q
Cumulative frequency distribution is non-decreasing. (T/F)
A
TRUE
16
Q
Both dot plots and stem-and-leaf displays can be used to detect possible outliers. (T/F)
A
TRUE
17
Q
Which in the following is (are) used to describe the central tendency of a data set? Check all that apply.
A
Mean, Mode, Median
18
Q
When data are symmetric, median is more common used to describe its central tendency.
A
FALSE
19
Q
percentile
A
a value such that p percent of the measurements fall at or below the value
20
Q
index
A
p/100*(n)
21
Q
Interquartile Range (IQR)
A
3rd quartile - 1st quartile
22
Q
5 number summary
A
- smallest measurement, 2. first quartile, 3. Median, 4. third quartile, 5. largest measurement
23
Q
Which of the following are part of the five-number summary? Check all that apply
A
median, 25th percentile
24
Q
Mean
A
average
25
Median
the middle number, average if there are an even number of elements
26
Mode
The value which appears most (THERE CAN BE MORE THAN ONE MODE)
27
Compare the means in the figure that shows three frequency distributions with different variances (V=1, 2,10), are the means equal?
Yes
28
Below we list several variables. Which of these variables are quantitative and which are qualitative?
dollar amount-quant, net profit - quant, which exchange - qual, national debt - quant, advertising medium - qual
29
A population is a set of existing units. (T/F)
TRUE
30
A random sample is selected so that every element in the population has the same chance of being included in the sample. (T/F)
TRUE
31
Statistical inference is the science of using a sample of measurements to make generalizations about the important aspects of a population of measurements. (T/F)
TRUE
32
Cross-sectional data are data collected at the same point in time. (T/F)
TRUE
33
The number of sick days per month taken by employees for the last 10 years at Apex Co. is an example of time series data. (T/F)
TRUE
34
It is possible to use a random sample from a population to make statistical inferences about the entire population. (T/F)
TRUE
35
A ____________ is a subset of the units in a population.
Sample
36
Which of the following is a quantitative variable?
mileage of a car
37
When we are choosing a random sample and we do not place chosen units back into the population, we are
sampling without replacement
38
A stem-and-leaf display is a graphical portrayal of a data set that shows the data set's overall pattern of variation. (T/F)
TRUE
39
The relative frequency is the frequency of a class divided by the total number of measurements. (T/F)
TRUE
40
A bar chart is a graphic that can be used to depict qualitative data. (T/F)
TRUE
41
When looking at the shape of the distribution using a stem-and-leaf, a distribution is skewed to the right when the left tail is shorter than the right tail. (T/F)
TRUE
42
When establishing the classes for a frequency table, it is generally agreed that the more classes you use the better your frequency table will be. (T/F)
FALSE
43
The sample cumulative distribution function is nondecreasing.
TRUE
44
Leaves on a stem-and-leaf display should be rearranged so that they are in increasing order from left to right. (T/F)
TRUE
45
A(n) ______ is a graph of a cumulative distribution.
ogive plot
46
All of the following are measures of central tendency except the ____________.
range
47
Which percentile describes the first quartile, Q1?
25th
48
Which percentile describes the third quartile, Q3?
75th
49
If a population distribution is skewed to the right, then, given a random sample from that population, one would expect that the ____________.
median would be less than the mean
50
If the mean, median, and mode for a given population all equal 25, then we know that the shape of the distribution of the population is ____________.
symmetrical
51
The population mean is the average of the population measurements. (T/F)
TRUE
52
The mode is the measurement in a sample or population that occurs most frequently. (T/F)
TRUE
53
The median is said to be resistant to extreme values. (T/F)
TRUE
54
The range of the measurement is the largest measurement plus the smallest measurement. (T/F)
FALSE
55
The median is the value below which and above which approximately 50 percent of the measurements lie. (T/F)
TRUE
56
The pth percentile is a value such that (100−p) percent of the measurements fall at or below the value. (T/F)
FALSE
57
Compare the means in the figure that shows three frequency distributions with different variances (V=1, 2,10), are the means equal?
Yes
58
In an experiment of flipping a coin, what is the sample space?
Head and Tail
59
In an experiment of tossing a die, what is the sample space?
1, 2, 3, 4,5, 6
60
What example is used in this video to illustrate the conditional probability?
Toss a balanced die
61
When events A and B are independent, which of the following statement(s) is(are) true? Select all that apply.
P(A|B) = P(A) ; P(B|A) = P(B)
62
What question(s) you may ask yourself if you want to determine whether a given random variable is a discrete random variable? Check all that apply.
Is it a random variable? ; Is it discrete?
63
The number of emails you receive on Mondays is a discrete random variable.
TRUE
64
In this video, what is suggested to start from when given a problem?
start from translating the question in the problem from the plain language into statistical notations
65
After you have successfully translated your question from the plain language to statistical notations, for example, P(Y=2), what is the immediate question you may want to ask yourself to guide you towards the next step?
What is the distribution of Y?
66
What shape of a binomial distribution may look like?
All of the above is possible
67
According to this video, how many properties a binomial random variable has?
4
68
Which of the following may be a good example of binomial random variable? Check all that apply
the number of heads out of n tosses of a coin ; the number of females in a class of 50 students ; the number of students in a class of 20 that are blood type O.
69
What does the uniform distribution look like?
A horizontal line
70
What are the properties of normal distribution? Check all that apply.
Symmetrical ; Bell shaped
71
What is the probability of a random selected sample has a value within 2 standard deviation around the mean if the population is normally distributed?
95%
72
The cumulative normal table of standard normal distribution provides the probability corresponding to the area under the standard normal curve to the _______ of a z value.
left
73
Which of the following is the correct way to calculate P( -1.6 < Z < 0.5)?
P(Z < 0.5) - P(Z < -1.6)
74
An event is a collection of sample space outcomes.
TRUE
75
Two events are independent if the probability of one event is influenced by whether or not the other event occurs.
FALSE
76
Mutually exclusive events have a nonempty intersection.
FALSE
77
The probability of an event is the sum of the probabilities of the sample space outcomes that correspond to the event.
TRUE
78
If events A and B are mutually exclusive, then P(A|B) is always equal to zero.
TRUE
79
A ___________________ is a measure of the chance that an uncertain event will occur.
probability
80
A manager has just received the expense checks for six of her employees. She randomly distributes the checks to the six employees. What is the probability that exactly five of them will receive the correct checks (checks with the correct names)?
0
81
In which of the following are the two events A and B always independent?
The probability of event A is not influenced by the probability of event B, or P(A|B) = P(A).
82
What is the probability of rolling a seven with a pair of fair dice?
6/36
83
A coin is tossed 6 times. What is the probability that at least one head occurs?
63/64
84
The binomial experiment consists of n independent, identical trials, each of which results in either success or failure and is such that the probability of success on any trial is the same.
TRUE
85
A discrete random variable may assume a countable number of outcome values.
TRUE
86
The variable Home Ownership can take on one of two values, 1 if the person living in a home owns the home and 0 if the person living in a home does not own the home. This is an example of a discrete random variable.
TRUE
87
The mean of the binomial distribution is np(1 − p).
FALSE
88
In a binomial experiment, the results of one trial are dependent on the results of other trials.
FALSE
89
Which of the following is not a discrete random variable?
the number of minutes required to run 1 mile
90
A discrete probability distribution is expressed as a table, graph, or ___________ that gives the probability associated with each possible value that the random variable can assume.
formula
91
Which of the following statements about the binomial distribution is not correct?
The random variable of interest is continuous.
92
If n = 15 and p = .4, then the standard deviation of the binomial distribution is
Standard deviation = √npq = √[(15)(.4)(.6)] = √3.6 = 1.897
93
A uniform distribution f(x) is a continuous probability distribution, which says the probability that x is in any 2 intervals of equal length is the same.
TRUE
94
The actual weight of hamburger patties is an example of a continuous random variable.
TRUE
95
The number of defective pencils in a lot of 1000 is an example of a continuous random variable.
FALSE
96
All continuous random variables are normally distributed.
FALSE
97
For a continuous distribution, the exact probability of a particular value is zero.
TRUE
98
A continuous probability distribution having a rectangular shape, where the probability is evenly distributed over an interval of numbers, is called a uniform probability distribution.
TRUE
99
The ___________ is a graphic that is used to check visually whether data come from a normal population.
normal probability plot
100
The first step to constructing a normal probability plot is to
order the values in the data.
101
The random variable x has a uniform distribution when x lies between the values of 4 and 10. When x = 10, what is the value of f(x)?
0
102
The area under the normal curve between z = 0 and z = 1 is ________________ the area under the normal curve between z = 1 and z = 2.
greater than
103
If the random variable X has a mean of µ and a standard deviation σ, then the mean and standard deviation, respectively, of (X − µ)/σ are
0 and 1.
104
If the random variable x is normally distributed, ______ percent of all possible observed values of x will be within three standard deviations of the mean.
99.73
