How many feet in a mile

What is the equation of the circle with center (-3, 5) and radius 1.2?

lubasha [3.4K]

Hope this helps you.

5 0

4 years ago

The average number of words in a romance novel is 64,436 and the standard deviation is 17,071. Assume the distribution is normal

damaskus [11]

b. You're looking for the probability

Pr [72,972 ≤ X ≤ 90,043]

Transform X to Z ∼ Normal(0, 1) using the rule

X = µ + σ Z

with µ = 64,436 and σ = 17,071. Then the probability is

Pr [(72,972 - µ)/σ ≤ (X - µ)/σ ≤ (90,043 - µ)/σ]

≈ Pr [0.5000 ≤ Z ≤ 1.5000]

You probably have a z-score table available, so you can look up the probabilities to be about

Pr [Z ≤ 0.5000] ≈ 0.6915

Pr [Z ≤ 1.5000] ≈ 0.9332

and then

Pr [0.5000 ≤ Z ≤ 1.5000] ≈ 0.9332 - 0.6915 = 0.2417

c. The 75th percentile word count that separates the lower 75% of the distribution from the upper 25%. In other words, its the count x such that

Pr [X ≤ x] = 0.75

Transforming to Z and looking up the z-score for 0.75, we have

Pr [(X - µ)/σ ≤ (x - µ)/σ] ≈ Pr [Z ≤ 0.6745]

so that

(x - µ)/σ ≈ 0.6745

x ≈ µ + 0.6745σ

x ≈ 75,950

d. Because the normal distribution is symmetric, the middle 60% of novels have word counts between µ - k and µ + k, where k is a constant such that

Pr [µ - k ≤ X ≤ µ + k] = 0.6

Also due to symmetry, we have

Pr [µ - k ≤ X ≤ µ + k] = 2 Pr [µ ≤ X ≤ µ + k]

⇒ Pr [µ ≤ X ≤ µ + k] = 0.3

Transform X to Z :

Pr [(µ - µ)/σ ≤ (X - µ)/σ ≤ (µ + k - µ)/σ] = 0.3

⇒ Pr [0 ≤ Z ≤ k/σ] = 0.3

⇒ Pr [Z ≤ k/σ] - Pr [Z ≤ 0] = 0.3

⇒ Pr [Z ≤ k/σ] - 0.5 = 0.3

⇒ Pr [Z ≤ k/σ] = 0.8

Consult a z-score table:

Pr [Z ≤ k/σ] ≈ Pr [Z ≤ 0.8416]

⇒ k/σ ≈ 0.8416

⇒ k ≈ 14,367

Then the middle 60% of novels have between µ - k = 50,069 and µ + k = 78,803 words.

7 0

2 years ago

PLEASE help (desperate) :(

mars1129 [50]

Answer:

$4= \sqrt{16} \\1.5 = \sqrt{2.25}\\8 = 6^{2} /9*2\\1 = \frac{12 - 2}{6 + 4}\\5 = \sqrt{16 + 9} \\9 = 63/3^{2} +|2|$

6 0

3 years ago

37% of women consider themselves fans of professional baseball. you randomly select six women and ask each if she considers hers

valina [46]

Answer:

(a) 2.22

(b) 1.3986

(c) 1.183

Step-by-step explanation:

Let X denote the number of women who consider themselves fans of professional baseball.

The proportion of women who consider themselves fans of professional baseball is, p = 0.37.

A random sample of n = 6 women are selected and each was asked if she considers herself a fan of professional baseball.

Each woman's reply is independent of the others.

The random variable X thus follows a binomial distribution with parameters n = 6 and p = 0.37.

(a)

Compute the mean of the binomial distribution as follows:

$\text{Mean}=np=6\times 0.37=2.22$

(b)

Compute the variance of the binomial distribution as follows:

$\text{Variance}=np(1-p)=6\times 0.37\times (1-0.37)=1.3986$

(c)

Compute the standard deviation of the binomial distribution as follows:

$\text{Standard Deviation}=\sqrt{np(1-p)}=\sqrt{6\times 0.37\times (1-0.37)}=1.183$

5 0

3 years ago

(PLEASE ANWER) At Chestatee Middle School, 120 students are in the choir. The ratio of girls to boys in the choir is 5:3. What i

Korvikt [17]

5:3 = 120 : x
72 girls and 48 boys

Hope that helps!

6 0

4 years ago