1. The center is at 2.1 hurricanes. The spread is an IQR of 3 ( 4 - 1), with a range of 7 (7 - 0). The shape is skewed right.
2a. increase; b. same; c. inc.; d. same; e. inc.
3a. Since the data is skewed right (draw a little box-plot using the 5 # summary to see this clearly), the mean will be greater than the median. It is pulled up by the skewness.
3b. IQR = 3.3 - 2.8 = 0.5
1.5*IQR = 1.5*0.5 = 0.75
2.8 - 0.75 = 2.05 is the lower outlier fence
3.3 + 0.75 = 4.05 is the upper outlier fence
SO: 4.2 is a high outlier and the other two fish are not outliers.
Chapter 6 #25 is odd! Check is carefully! Here's a little work:
25b) z = 0.5; 0.5 is the lower bound and 999 is upper
25c) lower bound = z = -1.583 and upper bound = z = -0.75
25d) invnorm(0.25) = - 0.674 = z; invnorm(0.75) = z = 0.674; then do algebra to find Q1 and Q3; IQR = Q3 - Q1
1. Who = 200 adults
What: education level and smoking habits
When: ??
Where: mall
How: ??
Why: ??
2. two categorical variables: education level and smoking status
3a. 32/200 = 16%; b. 32/93 = 34.4%; c. 32/50 = 64%
4. 2 bars: one for smokers and one for non. The bars should both add to 100%. The HS part of smoker bar should be 64%, whereas the 4+ non should be the biggest (48%).
5. These data provide evidence of an association between smoking and education level. 64% of smokers had only a hs diploma, whereas 40.7% of non-smokers had only a hs diploma.
6. We have no idea if the behavior changes over time. This data was only taken at one point in time.
