Arandom sample of size 21 was taken from a normal population. the sample average was 9.87 and the sample sd was 1.17. at the significance level of 10%, what test should you use for testing whether the population mean equals 9.7?

You should be using a hypothesis test - One sample T test.   

The answer is given below.  

Test of mu = 9.7 vs not = 9.7  

The assumed standard deviation = 1.17    

N Mean SE Mean 90% CI Z P  

21 9.87000 0.25531 (9.45004, 10.28996) 0.67 0.506  

since P value is greater than 0.05 we accept the null hypothesis that the population mean equals 9.7

I’m going to infer you said parallel.solve for yy= -1/2x+7/4lines that are parallel have the same slope, different y intercept.so we know m is -1/2then from there solve for y intercept.