In a sample of 60 electric motors, the average efficiency (in percent) was 85 and the standard deviation was 2. Section 05.01 Exercise 12.a - Compute confidence interval; Find necessary sample size Find a 95% confidence interval for the mean efficiency. Round the answers to three decimal places.

95% confidence interval for the mean efficiency is [84.483 , 85.517].

Step-by-step explanation:

We are given that in a sample of 60 electric motors, the average efficiency (in percent) was 85 and the standard deviation was 2.

So, the pivotal quantity for 95% confidence interval for the population mean efficiency is given by;

          P.Q. = ~

where, = sample average efficiency = 85

             = sample standard deviation = 2

            n = sample of motors = 60

             = population mean efficiency

So, 95% confidence interval for the mean efficiency, is ;

P(-2.0009 < < 2.0009) = 0.95

P(-2.0009  < < 2.0009 ) = 0.95

P( < < ) = 0.95

P( < < ) = 0.95

95% confidence interval for = [ ,  ]

                                                 = [ , ]

                                                 = [84.483 , 85.517]

Therefore, 95% confidence interval for the population mean efficiency is [84.483 , 85.517].

if x decreases by 4 then y increases by 10

step-by-step explanation:

2/3x + 7 = 29

step-by-step explanation:

two thirds = 2/3

plus a number = x

at least 29 = 29

there for you should get 2/3x + 7 = 29