Notes on correlation
Friday, November 15, 2019
Thursday, November 7, 2019
Wednesday, October 30, 2019
Monday, October 28, 2019
Friday, October 18, 2019
Wednesday, October 2, 2019
Thursday, September 26, 2019
Thursday, September 19, 2019
Friday, September 13, 2019
Notes for Homework 4, due September 16
Notes on contingency tables
In Excel: the sum of a row will be of the form
=sum(a1:c1) where the letters are the changing indices
The sum of a column will be
=sum(a1:a5) where the numbers are the changing indices
Notes on the Central Limit Theorem
In Excel: In my version of Excel, the function that gives you the proportion less than a z-score is
=norm.dist(x, mean, standard_dev, cumulative)
The cumulative value should be 1 always.
If we are doing a Central Limit z-score based on the average of a sample, the instruction is changed as follows.
=norm.dist(x, mean, standard_dev/sqrt(n), cumulative)
where n is the size of the sample.
Notes on probabilities of independent trials
In Excel: Again, different versions of Excel have different spelling of functions, and in my version the function is
=binom.dist(r, n, p, cumulative)
If cumulative = 0, you get the value of exactly r successes in n trials.
If cumulative = 1, you get the value of at least r successes in n trials.
In Excel: the sum of a row will be of the form
=sum(a1:c1) where the letters are the changing indices
The sum of a column will be
=sum(a1:a5) where the numbers are the changing indices
Notes on the Central Limit Theorem
In Excel: In my version of Excel, the function that gives you the proportion less than a z-score is
=norm.dist(x, mean, standard_dev, cumulative)
The cumulative value should be 1 always.
If we are doing a Central Limit z-score based on the average of a sample, the instruction is changed as follows.
=norm.dist(x, mean, standard_dev/sqrt(n), cumulative)
where n is the size of the sample.
Notes on probabilities of independent trials
In Excel: Again, different versions of Excel have different spelling of functions, and in my version the function is
=binom.dist(r, n, p, cumulative)
If cumulative = 0, you get the value of exactly r successes in n trials.
If cumulative = 1, you get the value of at least r successes in n trials.
Wednesday, August 28, 2019
Wednesday, August 21, 2019
Monday, November 26, 2018
Saturday, November 3, 2018
Tuesday, October 23, 2018
Thursday, October 18, 2018
Thursday, October 4, 2018
Notes on how to use the Population Pyramid website
Here are the cohort number for each gender and the total of the sexes from all the cohorts from 99 down. (The 100+ does not register at 0.1% for either males or females.) The cohorts in bold are the ones where the percentage is greater than the next youngest five year cohort. If the birth rate about the same, you would expect that death rates would mean there would be less people in the 50-54 cohort than in the 45-49 group. In the United States, there was the big baby boom from 1945 through 1965. The last gasp of that increased birth rate is the reason the 50-54 cohort counts as a mode. We also had a smaller baby boom that ended in the past five years, the reason why the ages from 5-9 and 20-24 all count as modes.
Cohort Male Female Total
95-99 0.0% 0.1% 0.1%
90-94 0.2% 0.4% 0.6%
85-89 0.5% 0.7% 1.2%
80-84 0.8% 1.1% 1.9%
75-79 1.2% 1.4% 2.6%
70-74 1.7% 2.0% 3.7%
65-69 2.4% 2.7% 5.1%
60-64 2.9% 3.1% 6.0%
55-59 3.4% 3.5% 6.9%
50-54 3.5% 3.5% 7.0%
45-49 3.2% 3.1% 6.3%
40-44 3.2% 3.2% 6.4%
35-39 3.1% 3.1% 6.2%
30-34 3.4% 3.5% 6.9%
25-29 3.5% 3.4% 6.9%
20-24 3.7% 3.5% 7.2%
15-19 3.3% 3.1% 6.4%
10-14 3.3% 3.1% 6.4%
05-09 3.3% 3.1% 6.4%
00-04 3.1% 3.0% 6.1%
Thursday, September 27, 2018
Notes for Homework 6, Fall 2018
Link to the population pyramid website
Link to the New England Journal of Medicine page (click on the interactive graphic icon, needs Adobe Flash player)
Link to the New England Journal of Medicine page (click on the interactive graphic icon, needs Adobe Flash player)
Friday, September 21, 2018
Thursday, September 13, 2018
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