Plssss hellpppp i don't understand

A community college has a math placement exam that has a mean of 65 and a standard deviation of 8.2. If a student takes the exam

Marat540 [252]

Answer:

The score that cuts off the bottom 2.5% is 48.93.

Step-by-step explanation:

When the distribution is normal, we use the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this question, we have that:

$\mu = 65, \sigma = 8.2$

What is the score that cuts off the bottom 2.5%

This is X when Z has a pvalue of 0.025, so X when Z = -1.96.

$Z = \frac{X - \mu}{\sigma}$

$-1.96 = \frac{X - 65}{8.2}$

$X - 65 = -1.96*8.2$

$X = 48.93$

The score that cuts off the bottom 2.5% is 48.93.

8 0

3 years ago

Read 2 more answers

Which of the following is true of the discriminant for the graph below?

Sonbull [250]

Answer:

<u>Option C. It is zero</u>

Step-by-step explanation:

The graph represents a quadratic equation

The quadratic equation has the form ⇒a x² + b x + c

The discriminant of the quadratic equation is D = b² - 4ac

From the discriminant of the quadratic equation, we can know the type of roots of the quadratic equation.

If D > 0 ⇒ Two real roots.
If D = 0 ⇒ one real roots
If D < 0 ⇒ Two imaginary roots.

The roots of the quadratic equation are the x-intercepts of the function.

As shown at the figure, the quadratic equation has only one point of intersection with the x-axis

So, the function has only one root ⇒ D = 0

So, the discriminant of the quadratic equation = 0

<u>The answer is option C. It is zero</u>

7 0

3 years ago

4(x-11)^2=25

netineya [11]

Expand the square: 4(x-11)^ =25
4(x-11)(x-11)=25

Distribute : 4(x-11)(x-11)=25
4(x(x-11)-11(x-11))=25

Distribute: 4(x(x-11)-11(x-11))=25
4(x^-11x-11(x-11))=25

Solution: x=17/2
x=27/2

hope that helps

8 0

3 years ago

If the area of sector AOC is 12π cm² and the measure of the radius is 6 cm, what is the measure of the central angle in radians?

ella [17]

Answer:

C

Step-by-step explanation:

7 0

3 years ago

The perimeters of similar triangles are in the same ratio as the corresponding sides

wariber [46]

Answer:

Always

Step-by-step explanation:

Suppose you have triangle ABC with side lengths a, b, c. Suppose that is similar to triangle DEF with side lengths d, e, f.

Now, let k be the ratio of corresponding sides ...

k = d/a

Because the same factor applies to all sides, we also have ...

k = e/b = f/c

That is, if we multiply by the denominators of each of these fractions, we get ...

d = a·k
e =b·k
f = c·k

The perimeter of ΔABC is ...

perimeter(ABC) = a + b + c

The perimeter of ΔDEF is ...

perimeter(DEF) = d + e + f = a·k + b·k + c·k

perimeter(DEF) = k(a + b + c) = k·perimeter(ABC)

k = perimeter(DEF)/perimeter(ABC)

That is, the perimeters are in the same ratio as corresponding sides.

3 0

3 years ago

Plssss hellpppp i don't understand​

Plssss hellpppp i don't understand