Is -24 a solution to the equation -16 + 2x =

A scientist studying water quality measures the lead level in parts per billion (ppb) at each of 49 randomly chosen locations al

NeX [460]

Complete Question

The complete qustion is shown on the first uploaded image

Answer:

The correct option is B

Step-by-step explanation:

From the question we are told that

The sample size is $n = 49$

The mean is $\mu = 17ppb$

The standard deviation is $\sigma = 14 ppb$

Generally the standard error of this measurement is mathematically represented as

$\sigma_z = \frac{\sigma}{\sqrt{n} }$

substituting values

$\sigma_{\= x} = \frac{14}{\sqrt{49} }$

$\sigma_{\= x} = 2$ ppb

Now the probability that the mean lead level from the sample of 49 measurements T is less than 15 ppb represented as P(X < 15 )

Next is to find the z value

$z = \frac{\mu -\sigma }{\sigma_{\= x}}$

$z = \frac{15-17}{2}$

$z = -1$

Now checking the z-table for the z-score of -1 we have

$P(X$

5 0

2 years ago

Sameer polled a random selection of 120 of the 250 workers at his office to determine whether they were satisfied with their off

jeka57 [31]

The margin of error can be calculated with the formula:

ME = z · √(p(1-p)/n)

where:
p = sample proportion
n = sample size
z = z-score

In your case:
p = 90 / 120 = 0.75

ME = 2.58 · √(0.75·0.25/120)
= 0.10
= 10%

The margin of error will be 10%.

6 0

2 years ago

Read 2 more answers

The product of a number and 3 more than twice the number is 275. Find the number.

Gnom [1K]

Answer:

55

Step-by-step explanation:

if you do 3 times a number, 3x and twice more, 2x , that would be 5x divided by 275 which would be 55.

5 0

2 years ago

A water well is being drilled in the desert where soil is either rock, clay, or sand. Probability of rock P(R) = 0.42, probabili

andrezito [222]

We are asked to solve for:

P (sand | positive)

So, we solve this by:

P (sand | positive) = P (sand) x P (positive for sand)

P (sand | positive) = 0.26 (0.75)

P (sand | positive) = 0.195

The probability is 0.195 or 19.5%.

6 0

2 years ago

Read 2 more answers

Liza's cousin Marie bought her a ring for 250 euros in France. Liza wants to pay Marie for it in U.S. dollars. If the foreign ex

EleoNora [17]

Answer:

416.67 dollars

Step-by-step explanation:

the exchange rate between U.S. dollar and euro is given as

Exchange rate = 1:0.6

1 U.S. dollar /1 euro = 0.6

cross-multiplying both side

1 x 1 U.S. dollar = 0.6 x 1 euro

1 U.S. dollar = 0.6 euro

multiplying both side by 10

10 U.S. dollar = 0.6 x 10 euro

10 U.S. dollar = 6 euro

dividing both side by "6"

10 U.S. dollar/6 = 6 euro/6

(10/6) U.S. dollar = 1 euro

1 euro = (10/6) U.S. dollar

the ring was bought for 250 euros , we need to convert 250 euros in dollars.

multiplying both side by 250

250 x 1 euro = (250 x 10/6) U.S. dollar

250 euro = 416.67 U.S. dollar

so liza should pay 416.67 U.S. dollar to marie.

4 0

2 years ago

Is -24 a solution to the equation -16 + 2x = - 64?