Stats TEST 1 PREP

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 Author: ballinbc14 ID: 61709 Filename: Stats TEST 1 PREP Updated: 2011-02-18 02:56:43 Tags: Stats 1100Q preparation test Folders: Description: Basic preparation for Stats 1100Q Show Answers:

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1. what are the 2 types of data?
• Categorical
• Quantitative
2. What is Categorical data?
Data made up of categories (not numbers) with "usual meaning
3. How do you compute Relative Frequency?
Frequency divided by total
4. What is Statistics?
Science of using data to analyze questions of interest and draw conclusions.
5. What is the experimental unit?
It is the object which you are studying
6. What is the experimental unit if you're studying the GPA of students?
Each individual student
7. What is a population in statistics?..give example.
• A collection of all experimental units of interest
• Ex: an entire student body
8. What is a statistical census?
This is a method for finding attributes of all members of a statistical population of interest
9. What is a statistical sample?
A subset of an entire population
10. What are the 3 major branches of statistics?
• Descriptive
• Probability
• Inferential
11. What is Descriptive Statistics?
Utilizes techniques to describe attributes of data sets
12. What is Probability Statistics?
This tells us what sorts of inferences we can make about a population based on the sample
13. What is Inferential Statistics?
Drawing conclusions from a sample that might be applicable to the whole population
14. What is a statistical variable?
A characteristic of the experimental unit of interest
15. What are the 2 types of variables?
Categorical and Quantitative
16. What is a quantitative variable?..and give an example.
• Variable that has natural ordering and are numeric
• Ex: Money
17. What is a discrete quantitative variable and give an example.
• This is a quantitative variable that can only take discrete numerical values?
• Ex: Integers
18. What is a continuous quantitative variable..example?
• This is a variable that can take on any numerical value
• Ex: All Real #s
19. If a variable is bounded, can it not qualify as continuous..exxample?
• No. A variable can be bounded and still be continuous.
• Ex: Non-negative #s
20. Found by adding up all of our data and dividing
by number of data points
Mean
21. If a statistical attribute (ex: mean) changes a lot when we change large values and changes little when we change little values then it is:
Not Resistant
22. Is mean a resistant statistical attribute?
No
23. What is median?
The middle value when a set of sample #s are ordered numerically
24. If a statistical attribute (ex: median) doesn't change at all when a new value is introduced to it then it is...
Resistant
25. Is median resistant?
Yes
26. If you have an even number of values, how do you find their median when ordered numerically?
the median is the mean of the middle 2 values in the order.
27. If the mean is roughly equal to the median, what shape would you expect your data set to be?
Symmetric
28. What cane you say about the shape of the data if the mean is greater or less than the median?
If mean is greater then positive skewed; if less than the median then it is negatively skewed
29. What is the mode?
The value that appears most often

30. This is specifically the equation for...
Sample Standard deviation

31. This is the formula for...
And what does Mu stand for in this?
• Population Standard Deviation
• Mu is population mean

32. This is the formula for
Sample Variance (Standard Deviation squared)
33. What are Q1, Q2, and Q3 for IQR?
• Q1=Median of 1st half of data set
• Q2= median of full set
• Q3= Median of 2nd half of set
34. Are the quartiles in IQR and the IQR itself resistant?
yes
35. If you have an odd number of data, what do you do with the middle value when calculating quartiles?
The middle value is included in both Q1 and Q3 calculations.
36. Name the resistant measures of spread and center
• mean
• IQR
37. Name the non-resistant measures of spread and center
• mean
• range
• standard dev
38. How do you designate the range in which a value is considered and outlier?
• If it is less than Q1-1.5*IQR
• or
• If it is greater than Q3+1.5*IQR
39. When can you drop and observation from a data set?
• When you are certain of it being a mistake
• When you know the observation came from the wrong population
40. What does the Empirical rule say about data?
68% of data falls within the first standard deviation, 95% falls within the second standard deviation, and 99.7% of the data falls within 3 standard deviations
41. What are the characteristics of bell-shaped data?
• symmetric
• unimodal
• mean and median are relatively close to each other
42. How do you calculate statistical density?
• Density = Relative Frequency divided by group
• width
43. What are some topics you should include when summarizing a set of data
• shape