The diameter of a brand of tennis balls is approximately normally distributed, w
ID: 3045847 • Letter: T
Question
The diameter of a brand of tennis balls is approximately normally distributed, with a mean of 2.77 inches and a standard deviaton of 0.04 inch. A random sample of 10 tennis balls is selected. Complete parts (a) through (d) below a. What is the sampling distribution of the mean? O A Because the population diameter o tennis balls is approximately normally distributed the sampling dsnbution o samples o size 0 will be the uniform distribution. O B. Because the population diameter of tennis balls is approximately normally distributed, the sampling distribution of samples of size 10 will not be approximately normal. C. Because the population diameter o tennis balls is approximately normally distributed the sampling distribution o samples o size 0 cannot be un D Because he population dia meter o ennis balls is approximately normally distribu e the sampling disr bution of samples of size 10 w a so be approximate normal b. What is the probability that the sample mean is less than 2.74 inches? P(X2.74)- Round to four decimal places as needed.) c. What is the probability that the sample mean is between 2.75 and 2.79 inches? P(2.75c XExplanation / Answer
a) D - Sampling distribution will be approximately normal
b) Z=(2.74-2.77)/0.04=-0.75
P(z<-0.75)=0.226627
c) Z= (2.75-2.77)/0.04=-0.5 and +0.5
P(-0.5<z<0.5)=0.3829
d) 58 % means z value is 29% above mean.
Z = 0.806421 and -0.806421
Lower bound=2.77-0.806421*0.04=2.7377
Upper bound =2.77+0.806421*0.04=2.8022