Author Topic: Stastics Chi squared problem  (Read 1824 times)

Offline archie017

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Stastics Chi squared problem
« on: November 11, 2011, 12:42:54 pm »

1: Sleep apnea is a pattern of irregular breathing during sleep, with longer than normal breath-holding intervals. The following two-way table shows counts of men and women with sleep apnea or not, from a sleep study with 400 men and 300 women.

   Sleep Apnea?
Gender   Yes   No
Men            40   360
Women   12   288

a. Calculate the risk of sleep apnea for men in this study.


b. Calculate the risk of sleep apnea for women in this study.


c. Find the value that completes this sentence: The risk of sleep apnea for men is ___ times the risk for women. In other words, determine the relative risk.



d. Find the value that completes this sentence: The odds of sleep apnea for men are __ times the odds for women.  In other words, find the odds ratio.



Offline archie017

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Statistics Chi squared problem.
« Reply #1 on: November 11, 2011, 12:44:28 pm »
3 Using the HSB data:  The High School and Beyond data is from a large-scale longitudinal study conducted by the National Opinion Research Center (1980) under contract with the National Center for Education Statistics.  Below is a table (note: this is called summarized data!) representing a sample of 100 students from this data that includes the student’s gender and whether the high school they attended was public or private.  Note: if you did the activity for the probability lesson this would be a test of independence: that is, can we say that the probability of being Female is independent of the probability that school type is public?

   Public   Private   Total
Female   38   7   45
Male           46   9   55
Total           84   16   100

(i)   Complete following table using conditional percents (this would be the row percents),

   Public   Private   Total
Female         
Male         
Total         

(ii)   based on the percents, discuss the nature of any relationship, and

(iii)   do a chi-square test of statistical significance. State a clear conclusion for the test of significance.   





4: Suppose a newspaper article states that drinking three or more cups of coffee doubles the risk of gall bladder cancer. Before giving up coffee, what question(s) should be asked by a person who drinks this much coffee?  (There is more than one possible answer.)