Need help on 132 and 133 please! For sat the mean is 1498 and Standard deviation

Question

Need help on 132 and 133 please!

For sat the mean is 1498 and Standard deviation is 316

For ACT the mean is 21.5 with standard deviation of 5.4

up the top 12% of all scores? 131 How low is the bottom 12%? What SAT scores make up the bottom 12% of all scores? 132 Find the ACT quintiles. The quintiles of any distribution are the values with cumulative proportions 0.20, 0.40, 0.60, and 0.80. What are the quintiles of the distribution of ACT scores? 133 Find the SAT quartiles. The quartiles of any distribution are the values with cumulative proportions 0.25 and 0.75. What are the quartiles of the distribution of SAT scores? 134 Do you have enough "good cholesterol? High- density lipoprotein (HDL) is sometimes called the "good cholesterol" because low values are associated with a higher risk of heart disease. According to the American Heart Association, people over the age of 20 years should have at least 40 milligrams per deciliter (mg/d) of HDL cholesterol. U.S, women aned 20 and over have a mean

Explanation / Answer

Ans:

132.

For z value,we can use Excel function Normsinv or we can use z table for z value corresponding to cumulative probability.

e.g. z=normsinv(0.2)=-0.84

So,16.96,20.13,22.87 and 26.04 are 0.2,0.4,0.6 and 0.8 quintiles respectively.

133)

First quartile:

P(Z<=z)=0.25

z=-0.6745

x=1498-0.6745*316=1284.86

Third quartile:

P(Z<=z)=0.75

z=0.6745

x=1498+0.6745*316=1711.14

Quintiles z value x=21.5+z*5.4 0.2 -0.84 16.96 0.4 -0.25 20.13 0.6 0.25 22.87 0.8 0.84 26.04

Related Questions

Navigate

• Browse (All)
• Browse N
• Subjects

---

---

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