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makkiz [27]
3 years ago
14

5. [Statistical independence] Consider a month consisting of exactly 28 days, split into four weeks of seven days each, such tha

t the first of the month is a Monday. One of the 28 days will be selected uniformly at random (so that each day has probability 1/28 of being selected). Event A is that the selected day is a Monday or Wednesday. Event B is that the selected day falls either in the first or third weeks of the month. Are A and B independent or not? Show your work.
Mathematics
1 answer:
harina [27]3 years ago
3 0

Answer:

They are independent events

Step-by-step explanation:

For independent events;

Pr(A & B) = Pr(A) × Pr(B)

Given that:

A = day is Monday or Wednesday

Since we have four weeks and each week will have one Monday and Wednesday each,

Pr(A) = (8/28)

B = day falls in the first or third week

Since, first and the third week has a total of 14 days,

Pr(B) = 14/28

Therefore;

Pr(A) × Pr(B) = 8/28 * 14/28

Pr(A) × Pr(B)  = 1/7

Now, A and B = day is either Monday or Wednesday, and it is in the first or third week

There are four such days, Thus Pr(A and B) = 4/28 = 1/7

Since, Pr(A and B) = Pr(A) * Pr(B),

A and B are independent events

You might be interested in
The length of human pregnancies from conception to birth varies according to a distribution that is approximately normal with me
iragen [17]

Answer:

a) 229 and 305 days

b) 229 days or less

c) 305 days or more

Step-by-step explanation:

The Empirical Rule(68-95-99.7 rule) states that, for a normally distributed random variable:

68% of the measures are within 1 standard deviation of the mean.

95% of the measures are within 2 standard deviation of the mean.

99.7% of the measures are within 3 standard deviations of the mean.

In this problem, we have that:

Mean = 267

Standard deviation = 19

(a) Between what values do the lengths of the middle 95% of all pregnancies fall?_____________and___________days

By the Empirical rule, 95% of all pregnancies fall within 2 standard deviations of the mean.

So

267 - 2*19 = 229 days

to

267 + 2*19 = 305 days

(b) How short are the shortest 2.5% of all pregnancies?______days or less

95% of all pregnancies fall within 2 standard deviations of the mean. The other 5% are more than 2 standard deviations from the mean. Since the distribution is symmetric, 2.5% is more than 2 standard deviations below the mean(shortest 2.5%) and 2.5% is more than 2 standard deviations above the mean(longest 2.5%). So

267 - 2*19 = 229 days

c) How long do the longest 2.5% of pregnancies last?________days or more

Explanation in b)

267 + 2*19 = 305 days

7 0
3 years ago
An apartment building produces $4,000 per quarter in gross rents. The maintenance expenses run $350 per month. Property taxes ar
erica [24]

Answer:

0.16%

Step-by-step explanation:

Cost of rent per quarter = $4000

Cost of rent per year = 4×$4000

= $16,000

This means that the apartment building produces $12,000 per year in gross rents.

Yearly Expenses are as follows;

Maintenance expenses per year = 12×$350 = $4200

Property taxes per year = $1,750

Mortgage payment per year = 12×$650 = $7800

Total expenses per year = sum of all the yearly expenses

= $4200+$1,750+$7800

= $13750

Yearly revenue generated = Cost of rent per year - total yearly expenses

= $16,000-$13750

= $2250 (net operating income)

Capitalization rate is given as the ratio of the net operating income to the market value of the building.

Capitalization rate = net operating income/market value of building

Since the building with $83750, that will be its market value

Cap rate = $13750/$83750

Cap rate = 0.16%

6 0
3 years ago
A trail is 2 miles long. There is a marker every 1/8 mile. How many markers are there?
attashe74 [19]

Answer:

16

Step-by-step explanation:

Number of Markers =

2 \div  \frac{1}{8}  \\  = 2 \times 8 \\  = 16

8 0
3 years ago
What is the value of x in the equation 1,331x3 − 216 = 0?
erma4kov [3.2K]
1331 x³ = 216
x³ = 216/1331
x = \sqrt[3]{ \frac{216}{1331} } =  \frac{6}{11}
Thank you.
4 0
3 years ago
∆ABC transforms to produce ∆A'B'C'. Which transformation did NOT take place?
never [62]

Answer: The answer is (D) Reflection across the line y = -x.


Step-by-step explanation:  In figure given in the question, we can see two triangles, ΔABC and ΔA'B'C' where the second triangle is the result of transformation from the first one.

(A) If we rotate ΔABC 180° counterclockwise about the origin, then the image will coincide with ΔA'B'C'. So, this transformation can take place here.

(B) If we reflect ΔABC across the origin, then also the image will coincide with ΔA'B'C' and so this transformation can also take place.

(C) If we rotate ΔABC through 180° clockwise about the origin, the we will see the image will be same as ΔA'B'C'. Hence, this transformation can also take place.

(D) Finally, if we reflect ΔABC across the line y = -x, the the image formed will be different from ΔA'B'C', in fact, it is ΔA'D'E', as shown in the attached figure. So, this transformation can not take place here.

Thus, the correct option is (D).


6 0
3 years ago
Read 2 more answers
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