00:01
Do bonds reduce the overall risk of an investment portfolio? let x be a random variable representing annual percent return for vanguard total stock.
00:14
And y represent the annual return for balanced index.
00:24
For the past several years, we have the data that's been given to us, and we are to compute the following.
00:32
So first, the sum of x.
00:35
And this can be done with your statistical software or graphing calculator.
00:38
So entering in your x values into a list and then doing a one variable statistic will calculate these values for you.
00:50
So the sum of x is 61, the sum of x squared is 3 ,261.
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The sum of y is 68 and the sum of y squared is 1 ,800.
01:01
For part b, we're going to compute the sample mean, variance, and standard deviation for both.
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So the sample mean for x is 6 .1.
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The sample variance is 320 .95, excuse me, 9835.
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And the sample standard deviation is 17 .92.
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For y, the mean is 6 .8.
01:39
The variance is 148 .62, and the standard deviation is 12 .197.
01:47
For part c, compute a 75 % chevy -shev interval around the mean for x values and also for y values...