When you roll a pair of dice, there are several outcomes, as shown below:

A survey of shoppers is planned to determine what percentage use credit cards. prior surveys suggest 63% of shoppers use credit

Alona [7]

We would need a sample size of 560.

We first calculate the z-score associated. with this level of confidence:
Convert 95% to a decimal: 95% = 95/100 = 0.95
Subtract from 1: 1-0.95 = 0.05
Divide by 2: 0.05/2 = 0.025
Subtract from 1: 1-0.025 = 0.975

Using a z-table (http://www.z-table.com) we see that this is associated with a z-score of 1.96.

The margin of error, ME, is given by:
$ME=z*\sqrt{\frac{\hat{p}(1-\hat{p})}{n}}$

We want ME to be 4%; 4% = 4/100 = 0.04. Substituting this into our equation, as well as our proportion and z-score,
$0.04=1.96\sqrt{\frac{0.63(1-0.63)}{n}}
\\
\\\text{Dividing both sides by 1.96,}
\\
\\\frac{0.04}{1.96}=\sqrt{\frac{0.63(0.37)}{n}}
\\
\\\text{Squaring both sides,}
\\
\\(\frac{0.04}{1.96})^2=\frac{0.63(0.37)}{n}
\\
\\\text{Multiplying both sides by n,}
\\
\\n(\frac{0.04}{1.96})^2=0.63(0.37)
\\
\\n(\frac{0.04}{1.96})^2=0.2331
\\
\\\text{Isolating n,}
\\
\\n=\frac{0.2331}{(\frac{0.04}{1.96})^2}=559.67\approx560$

3 0

3 years ago

Caleb and Mike both score the same amount of points in a game. Caleb has fifteen less than the total number of points. Mike has

elena-s [515]

Answer:
129 points
Step-by-step explanation:
Let L and C represent the scores of Luke and Caleb, respectively.
L = 2C -15 . . . . . Luke scored 15 less than twice the number Caleb did
L +C = 201 . . . . . they scored 201 points altogether
Add twice the second equation to the first:
2(L +C) + (L) = 2(201) + (2C -15)
3L +2C = 387 +2C . . . . simplify
3L = 387 . . . . . . . . . . . . .subtract 2C
L = 387/3 = 129 . . . . . . .divide by 3
Luke scored 129 points.

3 0

3 years ago

The curves y = √x and y=(2-x) and the Cartesian axes form two distinct regions in the first quadrant. Find the volumes of rotati

makkiz [27]

Answer:

Step-by-step explanation:

If you graph there would be two different regions. The first one would be

$y = \sqrt{x} \,\,\,\,, 0\leq x \leq 1 \\$