Use cross products to determine weather the pair of ratios forms a proportion. 5/15 and 30/90

The contents of 3838 cans of coke have a mean of x¯¯¯=12.15x¯=12.15. assume the contents of cans of coke have a normal distribution with standard deviation of σ=0.12.σ=0.12. find the value of the test statistic zz for the claim that the population mean is μ=12.μ=12.

What is the average rate of change for this function for the interval from x=2 to x=4 ?

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