Can someone plzzzz help meee with the last 3 problems!!! I really need help

2. The Welcher Adult Intelligence Test Scale is composed of a number of subtests. On one subtest, the raw scores have a mean of

IgorC [24]

Answer:

a) 37.31 b) 42.70 c) 0.57 d) 0.09

Step-by-step explaanation:

We are regarding a normal distribution with a mean of 35 and a standard deviation of 6, i.e., $\mu$ = 35 and $\sigma$ = 6. We know that the probability density function for a normal distribution with a mean of $\mu$ and a standard deviation of $\sigma$ is given by

$f(x) = \frac{1}{\sqrt{2\pi}\sigma}\exp[-\frac{(x-\mu)^{2}}{2\sigma^{2}}]$

in this case we have

$f(x) = \frac{1}{\sqrt{2\pi}6}\exp[-\frac{(x-35)^{2}}{2(6^{2})}]$

Let $X$ be the random variable that represents a row score, we find the values we are seeking in the following way

a) we are looking for a number $x_{0}$ such that

$P(X\leq x_{0})$ = $\int\limits^{x_{0}}_{-\infty} {f(x)} \, dx = 0.65$ , this number is $x_{0}$ =37.31

you can find this answer using the R statistical programming languange and the instruction qnorm(0.65, mean = 35, sd = 6)

b) we are looking for a number $x_{1}$ such that

$P(X\leq x_{1})$ = $\int\limits^{x_{1}}_{-\infty} {f(x)} \, dx = 0.9$ , this number is $x_{1}$ =42.70

you can find this answer using the R statistical programming languange and the instruction qnorm(0.9, mean = 35, sd = 6)

c) we find this probability as

$P(28\leq X\leq 38)$ = $\int\limits^{38}_{28} {f(x)} \, dx = 0.57$

you can find this answer using the R statistical programming languange and the instruction pnorm(38, mean = 35, sd = 6) -pnorm(28, mean = 35, sd = 6)

d) we find this probability as

$P(41\leq X\leq 44)$ = $\int\limits^{44}_{41} {f(x)} \, dx = 0.09$

you can find this answer using the R statistical programming languange and the instruction pnorm(44, mean = 35, sd = 6) -pnorm(41, mean = 35, sd = 6)

6 0

3 years ago

Read 2 more answers

Louis has three more quarters than dimes in his pocket, for a total of $1.80. which of the following equation could be used to d

vodka [1.7K]

Number of dimes: x
Number of quarters: x + 3
Answer:
B ) 0.10 x + 0.25 ( x + 3 ) = $1.80
Also we can solve this equation:
0.10 x + 0.25 x + 0.75 = 1.80
0.35 x = 1.80 - 0.75
0.35 x = 1.05
x = 1.05 : 0.35
x = 3, x + 3 = 6
He has 6 quarters and 3 dimes.
( 6 * 0.25 + 3 * 0.10 = 1.50 + 0.30 = $1.80 - correct)

7 0

3 years ago

What happens to the value of the expression \dfrac5x+5 x 5 +5start fraction, 5, divided by, x, end fraction, plus, 5 as xxx de

aleksandr82 [10.1K]

Answer:

It increases

Step-by-step explanation:

(5/x) + 5

As x decreases, 5/x increases. So the expression increases.

5 0

3 years ago

Read 2 more answers

Here are two shapes with the same area. Work out the perimiter of the rectangle.

Lilit [14]

So, we know the perimeter is 24 cm. and the top part is the left part, (x) + 2, but remember, we need to have it be a number that, multiplied by 2, is 24. So, using this formula, the length, (top / bottom) is 7, and x = 5. Because 5 + 5 = 10, and when length is +2, it adds up to 14. 10 + 14 = 24. So, length is 7, width, (left, right) is 5.

3 0

3 years ago

How do I get the answer to 6x+2=14

Eddi Din [679]

The answer for 6x+2=14 is x=2.

8 0

3 years ago