A standard deviation of 10 values is 8.19. You add 5 points to each score in the sample. The standard deviation for the new sample is:

a. Grand Mean = 2.799

b. Standard Deviation = 0.01387

c. Standard Error = 0.0016

d. The range with a Z score of 3 = (2.75739, 2.84061)

Step-by-step explanation:

a. Grand mean :

Given that

Sum of 80 values = 223.91

Total observation = 80

Grand mean = 223.91/80 = 2.799

b. With the excel command "STDEV[range of cells]", we get the standard deviation as = 0.01387

c. Standard error =  Standard deviation / root of n

d. The range with a Z score of 3 :

lower limit = mean - (3 * SD) = 2.799 - (0.04161) = 2.75739

upper limit = mean + (3 * SD) = 2.799 + (0.04161) = 2.84061

a. Grand Mean = 2.799

b. Standard Deviation = 0.01387

c. Standard Error = 0.0016

d. The range with a Z score of 3 = (2.75739, 2.84061)

Step-by-step explanation:

a. Grand mean :

Given that

Sum of 80 values = 223.91

Total observation = 80

Grand mean = 223.91/80 = 2.799

b. With the excel command "STDEV[range of cells]", we get the standard deviation as = 0.01387

c. Standard error =  Standard deviation / root of n

d. The range with a Z score of 3 :

lower limit = mean - (3 * SD) = 2.799 - (0.04161) = 2.75739

upper limit = mean + (3 * SD) = 2.799 + (0.04161) = 2.84061

SI=(P*R*T)/100

P=2000

R=1.5

T=6

SI=(2000*1.5*6)/100

=(2000*9)/100

=180

Neil will earn interest of 180

Cost of 7 gallons=$24.50

Cost of 1 gallon=24.50/7=3.5

Cost of 15 gallons=15*3.5=52.5

Cost of 15 gallons will be $52.5

For 1 flavor there are 9 topping

Therefore, for 5 different flavors there will be 5*9 choices

No of choices= 5*9

=45 

The answer is in the image 

For every 8 cars there are 7 trucks

Therefore,

Cars:Truck=8:7

Answer is B)8:7

The answer is in the image