HCD 300 - Homework 2
What is the possible range of values for a correlation coefficient?
- -1.0 to 1.0
Given the following data, what is the correlation between age and length of sentence? Respondent: 1,2,3,4 Age (x): 14,15,15,20,16 [average=16] Length of Sentence (months): 80,65,155,192,123 [average=123]
- .79
Which of the following correlations would be interpreted as a strong relationship? (choose one or more)
- .80 - .70 ? - .60 ?
Given the following data, what is the correlation between income and education? Income: $36,577, $54,365, $33,542, $65,654, $45,765, $24,354, $43,233, $44,321, $23,216, $43,454, $64,543, $43,433, $34,644, $33,213, $55,654, $76,545, $21,324, $17,645, $23,432, $44,543 Education: 11, 12, 10, 16, 11, 7, 12, 12, 9, 12, 14, 13, 12, 10, 15, 16, 10, 10, 9, 15
- .87
What is the variance (s2) of the following set of scores? 12, 25, 6, 9, 16, 13, 11, 10, 8, 7, 6, 14, 16, 12, 11, 23
- 30.13
What is the standard deviation (s) of the following set of scores? 12, 25, 6, 9, 16, 13, 11, 10, 8, 7, 6, 14, 16, 12, 11, 23
- 5.49
What is the range of the following set of scores? 13.7, 53.2, 4.1, 9.3, 52.1, 32.5, 22.9, 41.5, 23.0, 15.5, 1.9, 33.2
- 51.3
A positive correlation means that there is a strong relationship between the variables.
- False
If there is a strong correlation between two variables (x and y) it is safe to assume that x caused y.
- False
True or False, the purpose of computing correlations is to find a causal relationship.
- False
Calculate a correlation matrix for the following data. Which two variables have a strong positive relationship? Fructosamine: 152,173,174,175,176,183,188,192,202,205,210,215,220,258 # of Group Visits Attended: 6,5,4,4,3,2,3,3,2,2,1,2,2,1 Infant Birthweight in Grams: 3175,3225,3350,3400,3530,3540,3525,3650,3600,3550,3950,3335,4500,4800
- Infant birthweight and frusctosamine
Which of the following measures of central tendency can be used for nominal level data? (choose one or more)
- Mode
Which of the following descriptive statistics can be used for ratio data? (choose one or more)
- Mode - Variance - Mean - Standard Deviation
A survey for kindergartners asked about their favorite color. The children were asked to check the box corresponding to blue, red, green, yellow, or orange. What is the scale of measurement for this question?
- Nominal
The three measures of variability commonly used to reflect the spread or dispersion in a group of scores are the standard deviation, the variance, and the _________?
- Range
Researchers collect data about JUULing by asking users to keep track of the number of times per day they turn their device on and the number of inhalations each time they turn the device on. What type of data are these?
- Ratio
What level of measurement is household income?
- Ratio
A perfect negative correlation would be represented by Pearson's r of -1.
- True
A perfect positive correlation would be represented by Pearson's r of 1.
- True
True or False, the sum of the deviations from the mean will always equal 0.
- True
Researchers collect continuous data with values ranging from 0-100. In the analysis phase of their research they decide to categorize the values in different ways. Given the way the researchers are examining the data - determine if the data would be considered nominal, ordinal or ratio (you may use choices more than once).
- Two categories (low vs. high) frequency (count) of values between 0-49 and frequency of values between 50-100 - ordinal - Three categories (low, medum, high) frequency (count) of values between 0-25, 26-74, & 75-100) - ordinal - Analyze each number in the set individually - ratio
What value is obtained by squaring the standard deviation?
- Variance
In this scatterplot: the x axis = national income per person y axis = scale of happiness Which of the following statement(s) is(are) TRUE (choose one or more) [happiness v income]
- as happiness goes up so does income - this scatterplot shows a direct relationship
In this scatterplot: x axis = scale of income inequality y axis = patents per million population Which of statement(s) is(are) TRUE? (choose one or more) [income inequality v patents]
- countries with greater income inequality are less innovative (have less patents per million population) - this scatterplot shows an indirect relationship
Researchers study the relationship between hours spent playing video games and GPA. They find that as the number of hours spent playing video games increases, GPA decreases. What type of relationship is this?
- negative relationship
Which of the following statement(s) is(are) TRUE (choose one or more) [metro health index & income plot]
- this scatterplot shows a direct relationship -this scatterplot shows the correlation between income and metro health index
Which of the following are nominal data? (choose one or more)
- three streets (Dove, Raven, Hawk) in a neighborhood - five categories of race - two categories of exposure to a treatment (exposed and unexposed)
