"ONE"-derful
Identify the type of bias involved.
1) An agricultural scientist wants to determine the effect of fertilizer type on the yield of tomatoes. The scientist sent questionnaires to 100 tomato growers. The type of fertilizer did not significantly affect the yield according to the 15 growers who responded.
2) A highway billboard listed a telephone number and a message for drivers to call that number to report their opinion of the new highway interchange.
3) A political candidate claims on his website that only of the public support a proposal that a competing candidate is sponsoring.
1) Nonresponse bias
2) Voluntary response bias
3) Self-interest bias
Given the following frequencies, compute the relative frequencies of each category. Round two 4 decimal places.
A: 23
B: 10
C: 35
D: 82
E: 47
A: 0.1168
B: 0.0508
C: 0.1777
D: 0.4162
E: 0.2386
Compute the mean, median, mode(s), and population standard deviation of the following data set. Round to 4 decimal places if necessary
23 40 33 10 90 23 40
Mean: 46
Median: 50
Modes: 23 and 40
Standard deviation: 27.2764
x y
80 2
70 1
50 4
20 8
10 7
1) Compute the correlation coefficient for the data above.
2) Assuming x and y are linearly related, what does this correlation coefficient indicate about the strength and direction of the linear association?
3) Based on this correlation coefficient, can we conclude about the slope of the least-squares regression line?
1) -0.9462
2) x and y have a strong, negative linear association.
3) Since the correlation coefficient is negative, the slope of the least-squares regression line must also be negative.
Identify each of the following as qualitative ordinal, qualitative nominal, quantitative discrete, or quantitative continuous.
1) Number of pairs of shoes owned
2) Starbucks drink sizes (short, tall, grande, venti)
3) Class grade (A, B, C, D, F)
4) First name
5) Weight of sumo wrestlers
1) Quantitative discrete
2) Qualitative ordinal
3) Qualitative ordinal
4) Qualitative nominal
5) Quantitative continuous
Fill in the blank.
1) In a stem-and-leaf plot, each ____ must be a single digit.
2) In a dot plot, the number of dots in a vertical column represents __________
3) In a time-series plot, the horizontal axis represents __________
1) leaf
2) the number of times a certain value appears in the data set (i.e. frequency)
3) time
Find Q1, Q2, and Q3.
36, 43, 18, 68, 13, 28, 39, 83, 5, 23, 37
Q1 = 18
Q2 = 36
Q3 = 43
Compute the least-squares regression equation (y = b0+b1x) for the given data set. Round the slope and y-intercept to 4 decimal places.
x y
6 5
3 3
1 2
4 7
5 1
y = 2.1622 + 0.3784x
Identify the sampling method used.
1) 49, 34, and 48 students are randomly selected from the Sophomore, Junior, and Senior classes with 496, 348, and 481 students respectively.
2) A sociologist conducts a survey that calls for describing and comparing the opinions of 4 different ethnic groups: African Americans, Asian Americans, European Americans, and Native Americans. The researcher selects a random sample of participants from each of the 4 predetermined subgroups.
3) An education researcher randomly selects 48 middle schools and interviews all the teachers at each school.
4) A researcher interviews 19 colleagues who work in his building.
1) Stratified
2) Stratified
3) Cluster
4) Convenience
1) In a data set, the number of items that are in a particular category is called the ________
2) In a data set, the proportion of items that are in a particular category is called the ________
3) A _________ is a bar graph in which the bars are ordered by size.
4) A ________ is represented by a circle in which the sizes of the sectors match the relative frequencies of the categories.
5) In bar graphs, the ________ of the bars represent the frequencies or relative frequencies.
1) In a data set, the number of items that are in a particular category is called the FREQUENCY
2) In a data set, the proportion of items that are in a particular category is called the RELATIVE FREQUENCY
3) A PARETO CHART is a bar graph in which the bars are ordered by size.
4) A PIE CHART is represented by a circle in which the sizes of the sectors match the relative frequencies of the categories.
5) In bar graphs, the HEIGHTS of the bars represent the frequencies or relative frequencies.
In a large sample of customer accounts, a utility company determined that the average number of days between when a bill was sent out and when the payment was made is 26 with a standard deviation of 4 days. Assume the data to be approximately bell-shaped.
1) Estimate the percentage of bills that were paid after more than 34 days.
2) Estimate the percentage of bills that were paid in less than 22 days.
1) 2.5%
2) 16%
When x and y are linearly related, the correlation coefficient can be interpreted as follows:
1) If r is positive, the linear association is ________
2) If r is negative, the linear association is ________
3) If r is close to -1, the linear association is ________ and ________
4) If r is close to 0, the linear association is _______
5) If r is close to 1, the linear association is ________ and ________
6) If r = 1, then x and y have a ___________ positive linear association.
7) If r = −1, then x and y have a ___________ negative linear association.
1) If r is positive, the linear association is POSITIVE
2) If r is negative, the linear association is NEGATIVE
3) If r is close to -1, the linear association is STRONG and NEGATIVE
4) If r is close to 0, the linear association is WEAK.
5) If r is close to 1, the linear association is STRONG and POSITIVE
6) If r = 1, then x and y have a PERFECT positive linear association.
7) If r = −1, then x and y have a PERFECT negative linear association.