37 terms

Statistics Exercises 1

Midterm exercises from chapter 1-6. Choose the correct word. Fill in the blank.

Terms in this set (...)

The value of variance and (range, coefficient of skewness) are never negative.
The measurement units of the (variance, standard deviation) are always the square of measurement units of the original data.
relative frequency
(Cumulative frequency, relative frequency) is the frequency of a class divided by the sum of all frequencies.
frequency polygon
(Ogive, frequency polygon) is a graph formed by joining the midpoints of the tops of succesive bars in a histogram by straight lines.
standard deviation
The (range, mean deviation, variance, standard deviation) is the most widely used measure of dispersion.
The (mean, median, mode) is the most widely used measure of central tendancy.
Consider the set of data 10, 10, 10, 20, 20, 20, 20. If one 20 is changed to 30, which of the following will remain the same? (mean, median, mode, range)
standard deviation
If the same number is added to all values, the (standard deviation, mean, mode) is unchanged.
quantitative variables
(Quantitative variables, qualitative variables) enable us to determine how much of something is possessed, not just whether it is possessed.
larger, smaller
Given data set A: 5 10 15 20 25
set B: 15 30 45 60 50
Standard deviation of set B is (smaller, larger) than standard deviation of set A.
Coefficient of variation of set B is (smaller, larger) than coefficient of variation of set A.
descriptive statistic
(Inferential statistic, descriptive statistic) consists of methods of organizing, displaying data by using tables, graphs and summary measures.
square root
The value of standard deviation is the (square, square root) of the variance.
relative frequency
(Coefficient of variation, relative frequency) is the ration of frequency of that class to the total frequency.
frequency polygon
(Histogram, frequency polygon) consists of line segments connecting the points formed by the class midpoint and the class frequency.
The valuable measure of central tendency when extremely large or small values occur is (mean, median, mode).
skewed to the right
The shape of distribution of scores which test appears to be difficult for the students is (symmetric, skewed to the right, skewed to the left).
A (small, large) value for a measure of dispersion indicates that the data are clustered closely around the mean.
mean, median
If the distribution is highly skewed, the (mean, median) would not be a good avergae to use. The (mean, median) would be more representative.
The standard deviation can never be (greater, smaller) than the range.
In positively skewed distribution, the mean lies to the (right, left) of the median.
Measure of dispersion that is not based on deviation from the mean is (range, variance).
Increasing the frequencies in the tails of a distribution will (increase, decrease) the standard deviation.
Generally, a (small, large) standard deviation implies that the measurements are clustered close to the mean.
The coefficient of skewness would be __________ if the mean of a frequency distribution is equal to the median and the mode.
__________ are graphical displays that summarize the main features of a set of data including the central tendancy, dispersion, symmetry and distances to the minimum and maximum values.
standard deviation
The __________ is the most widely used measure of dispersion.
If the lowest score were 40 and the highest score were 189, n=200, and we decide to group our scores into 15 classes for a frequency distribution, the width of each class would be __________.
In a group of 12 scores, the largest score is increased by 36 points. What effect will this have on the mean of the scores? The mean will be increased by __________ points.
quantitative, qualitative
The variable that can be reported numerically is known as __________ while the variable that is non-numeric is known as __________.
skewed to the left
If most students in BG1201 read Chapter 1 to Chapter 4 so carefully that they knew the answer to almost all questions on the quiz, the distribution of scores would be expected to be __________.
For a set of observations we have the following information: mean = $64, median = $61, mode = $60, standard deviation = $6, and range = $40. The coefficient of variation is __________ .
The mean of a data set is 3. If each data value is increased by 3 units, the mean is __________.
If we add an extremely high value in a data set, the mean of the set would be __________.
skewed to the right
A professor computed the mean, median and mode for the examination scores from a class of 60 students. More than half of the class had scores above the mode. The shape of the distribution is __________.
__________ is a measure of lack of symmetry of a distribution.
30, 3.2
A scientist is weighing each of 50 fish. He obtains a mean of 30g and a standard deviation of 3.2g. After completing the weighing, he finds that the scale was no aligned properly, and always under-reported every weight by 2g i.e., a fish that really weighed 26g was reported to weigh 24g. What are the mean and standard deviation after correcting for the error in the scale? Mean =__________ Standard deviation =__________
A line through the inside of a box-plot shows the value of the __________.