I NEED HELP WITH THIS ASAP!

Find the sum of -44, -10, and 49

Dmitriy789 [7]

Answer:

-5

Step-by-step explanation:

(-44) + (-10) + 49

=> 49 - 44 - 10

=> 49 - 54

=> -5

4 0

3 years ago

Read 2 more answers

The mean number of words per minute (WPM) read by sixth graders is 8888 with a standard deviation of 1414 WPM. If 137137 sixth g

Bingel [31]

Noticing that there is a pattern of repetition in the question (the numbers are repeated twice), we are assuming that the mean number of words per minute is 88, the standard deviation is of 14 WPM, as well as the number of sixth graders is 137, and that there is a need to estimate the probability that the sample mean would be greater than 89.87.

Answer:

"The probability that the sample mean would be greater than 89.87 WPM" is about $\\ P(z>1.56) = 0.0594$ .

Step-by-step explanation:

This is a problem of the distribution of sample means. Roughly speaking, we have the probability distribution of samples obtained from the same population. Each sample mean is an estimation of the population mean, and we know that this distribution behaves normally for samples sizes equal or greater than 30 $\\ n \geq 30$ . Mathematically

$\\ \overline{X} \sim N(\mu, \frac{\sigma}{\sqrt{n}})$ [1]

In words, the latter distribution has a mean that equals the population mean, and a standard deviation that also equals the population standard deviation divided by the square root of the sample size.

Moreover, we know that the variable Z follows a normal standard distribution, i.e., a normal distribution that has a population mean $\\ \mu = 0$ and a population standard deviation $\\ \sigma = 1$ .

$\\ Z = \frac{\overline{X} - \mu}{\frac{\sigma}{\sqrt{n}}}$ [2]

From the question, we know that

The population mean is $\\ \mu = 88$ WPM
The population standard deviation is $\\ \sigma = 14$ WPM

We also know the size of the sample for this case: $\\ n = 137$ sixth graders.

We need to estimate the probability that a sample mean being greater than $\\ \overline{X} = 89.87$ WPM in the distribution of sample means. We can use the formula [2] to find this question.

The probability that the sample mean would be greater than 89.87 WPM

$\\ Z = \frac{\overline{X} - \mu}{\frac{\sigma}{\sqrt{n}}}$

$\\ Z = \frac{89.87 - 88}{\frac{14}{\sqrt{137}}}$

$\\ Z = \frac{1.87}{\frac{14}{\sqrt{137}}}$

$\\ Z = 1.5634 \approx 1.56$

This is a standardized value and it tells us that the sample with mean 89.87 is 1.56 standard deviations above the mean of the sampling distribution.

We can consult the probability of P(z<1.56) in any cumulative standard normal table available in Statistics books or on the Internet. Of course, this probability is the same that $\\ P(\overline{X} < 89.87)$ . Then

$\\ P(z$

However, we are looking for P(z>1.56), which is the complement probability of the previous probability. Therefore

$\\ P(z>1.56) = 1 - P(z$

$\\ P(z>1.56) = P(\overline{X}>89.87) = 0.0594$

Thus, "The probability that the sample mean would be greater than 89.87 WPM" is about $\\ P(z>1.56) = 0.0594$ .

5 0

3 years ago

An introductory psychology class with n=44 students has 9 freshman males, 15 freshman females, 8 sophomore males, and 12 sophomo

andrezito [222]

Answer:

0.61

Step-by-step explanation:

Pr (female) = total number of females(n')/Total number of students(n)

Where P(female) = probability of selectinga female

Pr(female) = n'/n................. Equation 1

Given: n = 44 students, n' = 15+12 = 27 females

Substitute into equation 1

Pr(female) = 27/44

Pr(female) = 0.61.

Hence the probability of selecting a female is 0.61

3 0

3 years ago

Aubrey's dinner cost $85. She tips the waitstaff 30%, for excellent service.

Olin [163]

30% is equal to 0.3 (found by dividing the percentage by 100). Then we multiply the cost of dinner, $85, by 0.3 to find an answer of $25.50.

Answer: $25.50

6 0

3 years ago

Answer quickly! It very urgent

ra1l [238]

Answer: Because the graphs of the two equations overlap each other

Step-by-step explanation:

Every point on the first line also satisfies the second equation.

This is the same as equivalent fractions

where 1/2 = 2/4 = 3/6 = 4/8

Graphing these on a number line would only show one dot.

6 0

3 years ago