UPS Check Problem Solving Method

A random sample of size 100 was taken from a population. A 94% confidence interval to estimate the mean of the population was co

Firlakuza [10]

Answer:

Step-by-step explanation:

1) The z value was determined using a normal distribution table. From the normal distribution table, the corresponding z value for a 94% confidence interval is 1.88

The correct option is D

2) if 70% of all internet users experience e-mail fraud. It means that probability of success, p

p = 70/100 = 0.7

q = 1 - p = 1 - 0.7 = 0.3

n = number of selected users = 50

Mean, u = np = 50×0.7 = 35

Standard deviation, u = √npq = √50×0.7×0.3 = 3.24

x = number of internet users

The formula for normal distribution is expressed as

z = (x - u)/s

We want to determine the probability that no more than 25 were victims of e-mail fraud. It is expressed as

P(x lesser than or equal to 25)

The z value will be

z = (25- 35)/3.24 = - 10/3.24 = -3.09

Looking at the normal distribution table, the corresponding z score is 0.001

P(x lesser than or equal to 25) = 0.001

7 0

3 years ago

3x+(2x-5)=13-2(x+2)how much is this

Dimas [21]

Look at the pictures it explains the equation step by step tell me if you have any questions the answer is at the bottom

3 0

3 years ago

a car rental agency charge 20 per day plus 30 cents per mile. if you had one of the car for 5 days and your total bill is $197.5

Flura [38]

Answer:

325 miles

Step-by-step explanation:

$20 for each day

5 days

$0.30 for each mile

20(5) + 0.3x = 197.5

100 + 0.3x = 197.5

100 - 100 + 0.3x = 197.5 - 100

0.3x = 97.5

$\frac{0.3x}{0.3} = \frac{97.5}{0.3}$

x = 325

6 0

3 years ago

Which value from the set {1/2, 2/3, 4/3, 5/2} is a value of x that will the equation 3/4 ÷ × = 9/8 true?

Vitek1552 [10]

Answer:

2/3

Step-by-step explanation:

To find out what x is in this case, divide 3/4 by 9/8.

3/4 / 9/8

Dividing by a fraction is the same as multiplying it's inverse.

3/4 * 8/9

Cross cancellation (3 & 9 (GCF: 3); 4 & 8 (GCF: 4)

1/1 * 2/3

We can remove the 1/1.

2/3

2/3 is the value of x that will make 3/4 ÷ x = 9/8 true.

6 0

3 years ago

A sociologist wants to determine if the life expectancy of people in africa is less than the life expectancy of people in asia.

Colt1911 [192]

Answer:

The sample statistics are attached.

First, we need to determine the hypothesis.

The null hypothesis should be: $H_{o} : u_{africa} \geq u_{asia}$ .

The alternative hypothesis should be: $H_{a}: u_{africa}$

The next step is about calculating the t statistics based on the samples. This t test will give the probability value or p-value, which determines if there's enough to reject the null hypothesis. The formula we need to use to find the t-value is: $t=\frac{x_{1}-x_{2} }{\sqrt{\frac{s_{1} ^{2} }{n_{1} } +\frac{s_{2} ^{2} }{n_{2} } } }$

Replacing all the values into the formula, we have:

$t=\frac{52.4-58.1}{\sqrt{\frac{(7.4)^{2} }{45}+\frac{(8.8)^{2} }{35} } } \\t=\frac{-5.7}{\sqrt{1.2+2.2} } =\frac{-5.7}{1.8} =-3.2$

Therefore, the t-value is -3.2.

Now, we using a level of significance of 0.01, and a degree of freedom (df) of 34, we use the t-table to find the p-value for this results. (df = N -1; in this case, we take the smaller sample, which is 35, giving us 34 of df).

Therefore, according to the table attached, the p-value is less than 0.01, which is less than our level of significance. This result means that the null hypothesis is rejected. In other words, there's enough evidence to say that the life expectancy of people in Africa is less than the life of expectancy of people in Asia.

3 0

3 years ago