Word problems can be a little challenging, because you will have to read the con

Question

Word problems can be a little challenging, because you will have to read the concept, and try to link it with the statistical knowledge. There are two different kinds of questions: To find probability: Identify the normal variable X, and its population mean mu and population standard deviation sigma. Then follow procedures in 3(1). To find cut off value X_0: identify the normal variable x, and its population mean mu and population standard deviation sigma. Then follow procedures in 3(2). Please refer to the ekes note for the appropriate a procedure. Your body mass index (BMI) is your weight in kilograms dividend by the square of your height in meters. Many online BMI calculations allow you to enter weight in pounds and height in inches. High BMI is a common but controversial indicator of overweight or obesity. A study by the National center for Health Statistics found that BMI of American can young women (ages 20 to 29) is approximately Normal with mean 26.5 and standard deviation 6.4. People with BMI less than 18.5 are often classified as underweight. What percent of young women in America are underweight by this criterion? People with BMI over 30 are often classified as obese. What percent of young women in America are obese by this criterion? One medical research project decided to provide free treatment to the top 5% of the young women in terms of BMI. In order to qualify for the free treatment, how high does a young woman's BMI need to be?

Explanation / Answer

Sol:

normal distribution

mean=26.5

sd=6.4

Solution1:

P(X<18.5)--underweight

convert to z

z=x-mean/sd

=18.5-26.5/6.4

=-1.25

P(Z<-1.25)

To find P(Z<-1.25)

P(Z<-1.25)=1-P(Z<1.25)

=1-0.8944

=0.1056

0.1056*100=10.56% of population are underweight

Solution2:

P(X>30)---obese

convert to z

z=x-mean/sd

z=30-26.5/6.4

=3.5/6.4

=0.546875

=0.55

P(z>0.55)

To find P(Z>0.55)

P(Z>0.55)=1-P(z<0.55)

=1-0.7088

=0.2912

0.2912=29.12% of population are obese

Related Questions

Navigate

• Browse (All)
• Browse W
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.