Module 2 Stats
mean
the average value
Name the types of graphs that can be used for quantitative data.
1 Histogram 2 Frequency Polygon 3 Stem and Leaf Plot 4 Box Plot
Which of the datasets below has the largest variance? A 1, 3, 4, 7, 18 B 20, 22, 23, 24, 25 C 8, 8, 8, 8 D 13, 15, 16, 18
A Dataset A has the largest range; therefore, there is more variability in A. Notice that there is no variability in Dataset C.
What is one advantage of using a bar chart over a pie chart?
Unlike pie charts, bar charts can be used to display the frequencies for numerous categories and are, used more often to display the results from studies with large datasets.
For a negatively skewed distribution with a mean of 45 and a mode of 53, what value could be the median?
between 45 and 53 In negatively skewed data, the mean<median<mode; therefore, 45<median<53.
Describe the shape of a distribution if the mean is equals to the median. Positively skewed Negatively skewed Symmetric Unimodal
Unimodal
A frequency distribution polygon measures ______________________. either interval or ratio scales. Only nominal scales. Only ratio scales. Either nominal or ordinal scales.
either interval or ratio scales.
Calculate the variance for the dataset: 1, 4, 7. A 6 B 9 C 18 D 11
1+4+7= 12/3 mean= 4 sum of squares= (1-4)^2 + (7-4)^2= 18 degrees of freedom= 3-1=2 variance= sum of squares/ degrees of freedom variance= 18/ (3-1)= 18/2= 9
Identify each statement below that is true about pie charts. Select all that apply 1 Pie charts are the best for small datasets 2 Pie charts represent the relative frequency of each category 3 Researchers and statisticians typically do not use pie charts 4 Pie charts show the reader the number of items in the dataset
1, 2, 3
median
middle value when all scores are listed in ascending order
mode
the value in the dataset with the greatest frequency
You plot the exam scores using a histogram. If the bars of the histogram increase from left to right, what conclusion can be made? 1 There are more low scores than high scores. 2 There are more high scores than low scores. 3 Test scores improve over time. 4 The greater the study time, the higher the test score.
2 The exam scores are plotted along the horizontal axis and the frequency of each group of scores is plotted along the vertical axis. If the height (frequency) increases as you go from left to right, the low scores on the left have a smaller frequency than the high exam scores on the right.
For a positively skewed distribution with a mode of 30 and median of 36, what value could be the mean?
Greater than 36 In positively skewed data, the mode<median<mean. The median is 36, so the mean must be greater than 36.
What is a frequency table used for?
A frequency table shows the number of times a certain value occurs within a dataset, which is also known as each value's frequency
What is central tendency? Name 3 ways it can be measured.
A measure that represents the middle of values within a distribution. Mean, median, and mode.
The dataset from your research has a mean of 72.8 and a standard deviation of 2.6 for a sample of participants. How should you report the sample mean and standard deviation in a research journal?
M= 72.8, SD= 2.6 not x bar or s Note that when reporting the standard deviation of a sample, APA style uses M to represent the mean and SD to represent standard deviation.
Identify each measure that is affected by outliers. Select all that apply. Mean Median Mode Range Standard Deviation
Mean, Range, and Standard Deviation
The number of daily births at a New York hospital were totaled each day for one week (Monday through Sunday) with the following frequencies: 52, 66, 72, 57, 57, 43, 53. Create a frequency table
Monday- 52- 52/400=13%
Suppose you gathered data for the money spent ($ millions) over a 100- year period in five different geographic regions of the United States. What graph would best display your findings?
Three-dimensional graphs are more effective when used for three-dimensional data rather than for two-dimensional data. In this situation, there are three dimensions: $ millions spent, years, and geographic regions. Therefore, a three-dimensional graph would best display the data.
