In simplest form what is 2/7 + 2/5

A set of exam scores is normally distributed and has a mean of 80.2 and a standard deviation of 11. What is the probability that

ZanzabumX [31]

Answer:

93.32% probability that a randomly selected score will be greater than 63.7.

Step-by-step explanation:

Problems of normally distributed samples are solved using 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 problem, we have that:

$\mu = 80.2, \sigma = 11$

What is the probability that a randomly selected score will be greater than 63.7.

This is 1 subtracted by the pvalue of Z when X = 63.7. So

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

$Z = \frac{63.7 - 80.2}{11}$

$Z = -1.5$

$Z = -1.5$ has a pvalue of 0.0668

1 - 0.0668 = 0.9332

93.32% probability that a randomly selected score will be greater than 63.7.

5 0

3 years ago

Distribute 3(5x -1)<br> thank you<3.

AysviL [449]

Answer:

(3x5)+(3x-1) = 15+(-3)= 12

Step-by-step explanation:

There you go :)

7 0

3 years ago

Read 2 more answers

The probability that a grader will make a marking error on any particular question of a multiple-choice exam is 0.15. If there a

sashaice [31]

Answer:

$P(X=0)=(10C10)(0.15)^{0} (1-0.15)^{10-0}=0.1969$

$P(X \geq 1)= 1-P(X$

$P(X=0)=(nCn)(p)^{0} (1-p)^{n-0}=(1-p)^n$

$P(X \geq 1)= 1-P(X$

Step-by-step explanation:

Previous concepts

A Bernoulli trial is "a random experiment with exactly two possible outcomes, "success" and "failure", in which the probability of success is the same every time the experiment is conducted". And this experiment is a particular case of the binomial experiment.

The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".

The probability mass function for the Binomial distribution is given as:

$P(X)=(nCx)(p)^x (1-p)^{n-x}$

Where (nCx) means combinatory and it's given by this formula:

$nCx=\frac{n!}{(n-x)! x!}$

The complement rule is a theorem that provides a connection between the probability of an event and the probability of the complement of the event. Lat A the event of interest and A' the complement. The rule is defined by: $P(A)+P(A') =1$

Solution to the problem

Let X the random variable of interest, on this case we now that:

$X \sim Binom(n=10, p=0.15)$

what is the probability that no errors are made?

For this case means that all the questions were correct so we want this probability:

$P(X=0)=(10C10)(0.15)^{0} (1-0.15)^{10-0}=0.1969$

what is the probability that at least one error made?

For this case we want this probability:

$P(X \geq 1)$

And we can use the complement rule:

$P(X \geq 1)= 1-P(X$

If there are n questions and the probability of a marking error is p rather than 0.15, give expressions for the probabilities of no errors and at least one error

$P(X=0)=(nCn)(p)^{0} (1-p)^{n-0}=(1-p)^n$

$P(X \geq 1)= 1-P(X$

8 0

3 years ago

Don’t look at 2. But can someone help with one and fast ...????

elixir [45]

Answer:

a? sorry if it wrong

Step-by-step explanation:

7 0

3 years ago

Read 2 more answers

How do u do this.I need major help on it

Tpy6a [65]

Look for what 'y' is when t = 1 and t = 2. Go to the graph, look at 1 on the bottom axis and go up till you find the point, then go all the way to the left to see what the y-value is, in this case it should be 1200. If you do the same with t = 2, you will get 2400. So our two ordered pairs are:

(1, 1200), (2, 2400)

We can find the slope of these two points by plugging them into the slope formula:

$\sf m=\dfrac{y_2-y_1}{x_2-x_1}$

For points in the form of (x1, y1), (x2, y2). Plug in what we know:

$\sf m=\dfrac{2400-1200}{2-1}$

Subtract:

$\sf m=\dfrac{1200}{1}$

Divide:

$\sf m=1200$

This is the slope, so we can write the equation:

$\boxed{\sf y=1200t}$

4 0

3 years ago