Exam 1 Flashcards
Which of the following variables takes on values that are names or labels without natural ordering?
Continuous Variables
Discrete Variables
Ordinal Variables
Nominal Variables
Nominal Variables
Which of the following does NOT describe the center of a data set?
Mode
Mean
Variance
Median
Variance
_______ represents the spread of the data
Mode
Variance
Mean
Median
Variance
What is the IQR (inter-quartile range)?
75% = 35.99187
50% = 29.52519
25% = 23.31543
29.52519
6.20976
35.99187
12.67644
12.67644
Which of the following is NOT a correct explanation about ‘robust statistics’?
Median or iQR are usually considered as a robust statistics
For a symmetric distribution (with no outlier), non-robust and robust statistics usually provide the similar results
It refers to the descriptive statistics which is less sensitive to outliers or skewness of a distribution
If we have both extremely small and large observation, robust statistics might not be useful
If we have both extremely small and large observation, robust statistics might not be useful
Which of the following is the most appropriate graph to describe a categorical data?
Scatterplot
Boxplot
Histogram
Bar plot
Bar plot
Suppose that an anonymous questionnaire is given to patients at a dentist’s office once they arrive for an appointment. One of the questions asks “How often do you floss?”, and four answer options are provided: a) at least twice a day, b) at least once a day, c)a few times a week, and d) a few times a month. At the end of a week , the answers are tabulated: 31 individuals chose answer a), 55 choose b), 39 chose c), and 12 chose d).
What type of variable does the question imply?
Ordinal Variable
Numerical Variable
Discrete Variable
Nominal Variable
Ordinal Variable
Suppose that an anonymous questionnaire is given to patients at a dentist’s office once they arrive for an appointment. One of the questions asks “How often do you floss?”, and four answer options are provided: a) at least twice a day, b) at least once a day, c)a few times a week, and d) a few times a month. At the end of a week , the answers are tabulated: 31 individuals chose answer a), 55 choose b), 39 chose c), and 12 chose d).
How many levels do we have for the question?
1
2
4
3
4
Which of the following is NOT a property of a random variable?
A random variable represents numerical outcomes for different situation or events
A random variable cannot be negative
Each random variable has its own expectations
A random variable can be discrete or continuous
A random variable cannot be negative
For any probability distribution, the expected value:
is equal tot he random variable
cannot be grater than 1
is equal to the variance of the distribution
represents the location/center of the distribution
represents the location/center of the distribution
What is (5/2) or (5 choose 2)?
2.5
20
120
10
60
10
Which of the following is not a characteristic of binomial distribution?
The outcome of any trial is dependent on the outcome of the previous trials
For every trial, the probability of success is the same
The random variable can have a value of 2 or greater
The number of trials is fixed
The outcome of any trial is dependent on the outcome of the previous trials
The probability that a smoker will develop a severe lung condition in their lifetime is about 0.30. Suppose that five smokers are randomly selected from the population. What is the probability that more than four people will develop a severe lung condition?
0.0024
0.0284
0.0308
0.9692
0.0024
Which of the following is NOT a correct explanation for the Z-score?
An observation with z = 1.4 is more extreme (from the mean) value that the one with z = -1.6
It is useful to identify which observation are more extreme than others
z = (x-mean)/sd
it is useful when we compare observation from different normal distribution
An observation with z = 1.4 is more extreme (from the mean) value that the one with z = -1.6
What is the shape of a normal distribution curve?
half shape
bell shape
square shape
round shape
bell shape
Suppose that Z follows the standard distribution. What is P(Z>0.73) (round up two decimal places) use probability table of excel calculator
0.23
0.39
0.77
0.61
0.23
Suppose that Z follows the standard distribution. What is the value k satisfying P(Z>k) = 0.82? (round up two decimal places) use probability table of excel calculator
-0.92
0.92
0.21
0.79
-0.92
(round up two decimal places) use probability table of excel calculator
