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3 years ago

8 ? i need answers asap

Mathematics

1 answer:

Leona [35]3 years ago

4 0

Answer: SInce this is multiple choice I won't provide an explanation. The answers are B) (-1, -4) and E) (4, 6)

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Suppose you take a 30-question, multiple-choice test, in which each question contains 4 choices: A, B, C, and D. If you randomly

mina [271]

Answer:

(a) The probability you pass the exam is 0.0000501.

(b) The expected number of correct guesses is 7.5.

(c) The standard deviation is 2.372.

Step-by-step explanation:

We are given that you take a 30-question, multiple-choice test, in which each question contains 4 choices: A, B, C, and D. And you randomly guess on all 30 questions.

Since there is an assumption of only 1 correct choice out of 4 which means the above situation can be represented through binomial distribution;

$P(X =x) = \binom{n}{r}\times p^{r}\times (1-p)^{n-r} ; x = 0,1,2,3,......$

where, n = number of trials (samples) taken = 30

r = number of success = at least 60%

p = probbaility of success which in our question is the probability

of a correct answer, i.e; p = $\frac{1}{4}$ = 0.25

Let X = Number of questions that are correct

So, X ~ Binom(n = 30 , p = 0.25)

(a) The probability you pass the exam is given by = P(X $\geq$ 18)

Because 60% of 30 = 18

P(X $\geq$ 18) = P(X = 18) + P(X = 19) +...........+ P(X = 29) + P(X = 30)

= $\binom{30}{18}\times 0.25^{18}\times (1-0.25)^{30-18} + \binom{30}{19}\times 0.25^{19}\times (1-0.25)^{30-19} +.......+ \binom{30}{29}\times 0.25^{29}\times (1-0.25)^{30-29} + \binom{30}{30}\times 0.25^{30}\times (1-0.25)^{30-30}$

= 0.0000501

(b) The expected number of correct guesses is given by;

Mean of the binomial distribution, E(X) = $n \times p$

= $30 \times 0.25$ = 7.5

(c) The standard deviation of the binomial distribution is given by;

S.D.(X) = $\sqrt{n \times p \times (1-p)}$

= $\sqrt{30 \times 0.25 \times (1-0.25)}$

= $\sqrt{5.625}$ = 2.372

8 0

4 years ago

Find the geometric mean between 6 and 15<br><br> No decimals.

SVEN [57.7K]

Answer: it’s a decimal 9.5

Hope this helped!

8 0

3 years ago

15 out of 50 students have pets at home. What percent of the students have pets at home?

Vitek1552 [10]

Answer:

7.5

Step-by-step explanation:

divide 15 and 50

8 0

3 years ago

If you need how many days between two dates what function should be used

Mariana [72]

You have to do this piecemeal so there isn’t a single formula. The best way is to convert each date using a common frame of reference. Dates before October 1582 used a different calendar. Also the distance between leap years varies. It’s normally 4 years but it can be 8 years. For example, 2100 is not a leap year but 2096 and 2104 are both leap years. Similarly 1896 and 1904 but not 1900. Before October 1582 leap years occurred exactly 4 years apart.
Your next problem is to work out the day number from the beginning of the year. On average there are between 30.4 and 30.5 days in a month, but this is only an approximation because the length of each month varies. So to aid in the calculation you need a table which gives you the day number for every date in the year, and the table is different for leap years.
So, you start by subtracting the years and counting how many leap years there are between. You consult the day number table for working out how many days there are from the beginning of the year.
Another way is to have a smaller table with just the months, so in a non-leap year Jan 1 would be 1, Feb 1 would be 32, Mar 1 would be 60, Apr 1 would be 91, and so on. Then we have to add in the day date. Mar 20 would be 19 days after Mar 1 so would have a day number of 79, not 80. Some diaries and calendars include the day number.
You can speed up the calculation by using one day number table or calculation and then adding in a day for each leap year between two dates. I hope this helps.

6 0

4 years ago

Answer this plz thanks

lesantik [10]

The answer is greater than (>)

4 0

3 years ago

Read 2 more answers