Who wants a anime friend?

Describe in detail how you would construct a 95% confidence interval for a set of 30 data points whose mean is 20 and population standard deviation is 3. be sure to show that you know the formula and how to plug into it. also, clearly state the margin of error.

The manufacturer of a new product developed the following expression to predict the monthly profit, in thousands of dollars, from sales of the productwhen it is sold at a unit price of x dollars.-0.5x^2 + 22x - 224what is represented by the zero(s) of the expression? a. the profit when the unit price is equal to 0b. the unit price(s) when the profit is equal to 0c. the profit when the unit price is greatestd. the unit price(s) when profit is greatest

87.5% , 100% , 83.33 , 93.33% , 100% , 82.5% are all the academic points i've gotten this quarter. what's my final grade?