a local middle school has 99 computers and 333 students .what is the number of students per computer at the school

A report indicated that 37% of adults had received a bogus email intended to steal personal information. Suppose a random sample

fiasKO [112]

Answer:

5.05% probability that no more than 34% had received such an email.

Step-by-step explanation:

We use the binomial approximation to the normal to solve this problem.

Binomial probability distribution

Probability of exactly x sucesses on n repeated trials, with p probability.

Can be approximated to a normal distribution, using the expected value and the standard deviation.

The expected value of the binomial distribution is:

$E(X) = np$

The standard deviation of the binomial distribution is:

$\sqrt{V(X)} = \sqrt{np(1-p)}$

Normal probability distribution

Problems of normally distributed samples can be 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.

When we are approximating a binomial distribution to a normal one, we have that $\mu = E(X)$ , $\sigma = \sqrt{V(X)}$ .

In this problem, we have that:

$n = 700, p = 0.37$

$\mu = E(X) = np = 700*0.37 = 259$

$\sigma = \sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{700*0.37*0.63} = 12.77$

In a random sample of 700 adults, what is the probability that no more than 34% had received such an email?

34% is 0.34*700 = 238

So this probability is the pvalue of Z when X = 238.

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

$Z = \frac{238 - 259}{12.77}$

$Z = -1.64$

$Z = -1.64$ has a pvalue of 0.0505

5.05% probability that no more than 34% had received such an email.

7 0

4 years ago

A 16 inch candle is lit and burns at a constant rate of 1.1 inches per hour. Let t represent the never of hours that have elapse

Alex17521 [72]

Answer:

(a) Number of inches that have burned from the candle since it was lit is (1.1t) inches

(b) The remaining length of the candle is (16 - 1.1t) inches

Step-by-step explanation:

(a). Length of candle before it was lit = 16 inches

Constant rate at which at which candle burns = 1.1 inches per hour

Let t represent the number of hours that have elapsed since the candle was lit

In 1 hour, 1.1 inches of the candle burned

Therefore, in t hours, (1.1t) inches of the candle would have burned since the candle was lit

(b) Remaining length of candle = length of candle before it was lit - length of candle that have burned = 16 inches - 1.1t inches = (16 - 1.1t) inches

6 0

3 years ago

Whats is the measure of ikj

zimovet [89]

The is Answer: 202 because I answered it

6 0

3 years ago

Read 2 more answers

Mr. and Mrs. Delgado each own an equal number of shares of a stock.Mr. Delgado sells one-third of his shares for $2700. What was

liubo4ka [24]

3x2700=Just Mr. Delgado's shares' value= $8100

Since they own an equal number of shares, their total value of stock before the sale is two times what each of them has separately.

$8100 x 2=value of their stock= $16200

7 0

4 years ago

What is LP ? A. 36 B. 40 C. 44 D. 48 E. 52

Sonbull [250]

Answer:

The correct answer is option D. 48

Step-by-step explanation:

From the figure we can see that, some right angled triangles.

To find the measure of LP

Consider the right angled triangle LPT,

LT is the hypotenuse, LP = 50 units (given)

PT = QT = RT = 14 units

From figure we get,

LP² + PT² = LT²²

LP² = LT² - PT²

= 50² - 14²

= 2500 - 196

= 2304

LP =√2304

= 48

The correct answer is option D. 48

8 0

3 years ago