Can anyone help me solve this problem im not good at facorting

The amount of time devoted to studying statistics each week by students who achieve a grade of A in the course is a normally dis

svlad2 [7]

Answer:

a) 11.7% of students study for more than 10 hours per week.

b) 35.6% of student spends between 7 and 9 hours studying.

c) 1.6% of students spend fewer than 3 hours studying.

d) 5% of all A students spend studying 4.0455 or less hours during a week.

Step-by-step explanation:

We are given the following information in the question:

Mean, μ = 7.5 hours

Standard Deviation, σ = 2.1 hours

We are given that the distribution of amount of time is a bell shaped distribution that is a normal distribution.

Formula:

$z_{score} = \displaystyle\frac{x-\mu}{\sigma}$

a) P(students study for more than 10 hours per week)

P(x > 10)

$P( x > 10) = P( z > \displaystyle\frac{10 - 7.5}{2.1}) = P(z > 1.1904)$

$= 1 - P(z \leq 1.1904)$

Calculation the value from standard normal z table, we have,

$P(x > 10) = 1 - 0.883 = 0.117 = 11.7\%$

b) P(student spends between 7 and 9 hours studying.)

$P(7 \leq x \leq 9) = P(\displaystyle\frac{7 - 7.5}{2.1} \leq z \leq \displaystyle\frac{9-7.5}{2.1}) = P(-0.2380 \leq z \leq 0.7142)\\\\= P(z \leq 0.7142) - P(z < -0.2380)\\= 0.762 - 0.406 = 0.356 = 35.6\%$

$P(7 \leq x \leq 9) = 35.6\%$

c) P(students spend fewer than 3 hours studying)

$P(x < 3) = P(z < \displaystyle\frac{3-7.5}{2.1}) = P(z < -2.1428)$

Calculating the value from the standard normal table we have,

$P( x < 3) =0.016 = 1.6\%$

d) P(X < x) = 0.05

We have to find the value of x such that the probability is 0.035

$P( X < x) = P( z < \displaystyle\frac{x - 7.5}{2.1})=0.05$

Calculation the value from standard normal z table, we have,

$\displaystyle\frac{x - 7.5}{2.1} = -1.645\\x = 4.0455$

5% of all A students spend studying 4.0455 or less hours during a week.

5 0

3 years ago

Find the slope of the line through (2,-2) and 5,-1)

Kitty [74]

Answer:

$m=\frac{1}{3}$

Step-by-step explanation:

$\mathrm{Slope}=\frac{y_2-y_1}{x_2-x_1}\\\\\left(x_1,\:y_1\right)=\left(2,\:-2\right),\:\\\left(x_2,\:y_2\right)=\left(5,\:-1\right)\\\\m=\frac{-1-\left(-2\right)}{5-2}\\\\m = \frac{-1+2}{3}\\ \\Simplify\\m = \frac{1}{3}$

4 0

3 years ago

77 x - 8 = 17<br><br> I need an answer please!!!

Phoenix [80]

Answer:25 /77

Step-by-step explanation:

77 x - 8 = 17

Collect like terms

77 x = 17 + 8

x= 25 /77

3 0

2 years ago

Read 2 more answers

PLEASE HELP ME!!! 25 points!!!

aliya0001 [1]

1. In algebra, like terms are terms that have the same variables and powers.

2. What is combining like terms? We call terms "like terms" if they have the same variable part.

3. Polynomials form a system similar to the system of integers, in that polynomials are closed under the operations of addition, subtraction, and multiplication. CLOSURE: Polynomials will be closed under an operation if the operation produces another polynomial. ... Polynomials are closed under subtraction.

Hope this helps

7 0

2 years ago

True or False

attashe74 [19]

When we say right triangle, it is a triangle that has at least one angle equal to 90 degrees. In addition, an isosceles triangle can also be considered a right triangle given that it has two sides that are equal. In the given measurements above, the set is not considered as measurements of a right triangle. Therefore, the answer is FALSE. Hope this answer helps.

7 0

3 years ago

Read 2 more answers