I only need to know how to do C, everything I\'ve tried is quite off....The answ

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I only need to know how to do C, everything I've tried is quite off....The answer is {317 321} why is there two numbers for it?

p4 BIO 260, Spr 2014, Exam 1, Form A Name:_ (23) CALCULATIONS (3 pts each). Consider a data set of 1200 values that exhibits a normal distribution in which the mean is 60 and the standard deviation is 8. For the following questions, (a) Approximately what proportion of the data is less than 50? prop = (b) If a random value is chosen from this data set, prob_ what is the probability that it will be smaller than 64? (c) How many values in the data set are above 65? (d) What is the value of Q1? (e) What is the value of the data set's IQR? (f) What is the Coefficient of variation of the data set? (g) What is the median of the data set? (h) What is the kurtosis of the data set? # values = IQR = CV median Kurtosis

Explanation / Answer

here from normal distribution z=(X-mean)/std deviation

a) P(X<50)=P(Z<(50-60)/8)=P(Z<-1.25)=0.1056 ; 10.56%

b)P(X<64)=P(Z<(64-60)/8)=P(Z<0.5)=0.6915 ; 69.15%

c)for P(X>65) =1-P(Z<0.625)=1-0.7340=0.266

hence number of values =np=0.266*1200=319.2~319

d)as for 25 percentile , z=-0.6745

hence Q1=mean+z*std deviation =54.604

e)for 75 percentile , z=0.6745

Q3=mean+z*std deviation=65.396

hence IQR =Q3-Q1=10.792

f) CV=std deviation/mean =8/60=0.1333 ~13.33%

g) median for normal distribution =mean=60

h) kurtosis for normal distribution =3

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