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Given r=0.8,Sigma xy=60,sigma(y)=2.5 and...

Given `r=0.8,Sigma xy=60,sigma_(y)=2.5` and `Sigmax^(2)=90`, find the number of items, if x and y are deviation from their respective means.

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To solve the given problem step by step, we will use the provided values and relevant formulas. ### Given: - \( r = 0.8 \) - \( \Sigma xy = 60 \) - \( \sigma_y = 2.5 \) - \( \Sigma x^2 = 90 \) ### Step 1: Express the standard deviation formula for \( y \) The standard deviation formula for \( y \) can be expressed as: \[ \sigma_y = \sqrt{\frac{\Sigma y^2}{n}} \] Where \( \Sigma y^2 \) is the sum of the squares of the deviations of \( y \) from its mean, and \( n \) is the number of items.
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