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Dovator [93]
3 years ago
13

Suppose that 30% of all students who have to buy a text for a particular course want a new copy (the successes!), whereas the ot

her 70% want a used copy. Consider randomly selecting 15 purchasers.
The bookstore has 10 new copies and 10 used copies in stock.
If 15 people come in one by one to purchase this text, what is the probability that all 15 will get the type of book they want from current stock?
Mathematics
1 answer:
ValentinkaMS [17]3 years ago
6 0

Answer:

The probability that all 15 will get the type of book they want from current stock is 0.4838.

Step-by-step explanation:

Denote the random variable <em>X</em> as the number of students who want to buy new copy.

The probability of a student wanting to buy a new copy is, P (X) = <em>p</em> = 0.30.

A random sample of <em>n</em> = 15 students is selected.

The random variable <em>X</em> follows a Binomial distribution.

The probability function of a Binomial distribution is:

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

It is provided that the bookstore has 10 new copies and 10 used copies in stock.

All the 15 students get their desired copy, then this can happen if at most 10 want to buy new copy and at least 5 wants to buy used copy.

Compute the probability of (5 ≤ <em>X</em> ≤ 10) as follows:

P (5 ≤ <em>X</em> ≤ 10) = P (X = 5) + P (X = 6) + P (X = 7) + P (X = 8) + P (X = 9) + P (X = 10)

                     ={15\choose 5}(0.30)^{5}(1-0.30)^{15-5}+{15\choose 6}(0.30)^{6}(1-0.30)^{15-6}\\+{15\choose 7}(0.30)^{7}(1-0.30)^{15-7}+{15\choose 8}(0.30)^{8}(1-0.30)^{15-8}\\+{15\choose 9}(0.30)^{9}(1-0.30)^{15-9}+{15\choose 10}(0.30)^{10}(1-0.30)^{15-10}\\=0.2061+0.1472+0.0811+0.0348+0.0116+0.0030\\=0.4838

Thus, the probability that all 15 will get the type of book they want from current stock is 0.4838.

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Write a function min that has two str parameters and returns the smallest. (Smallest in the sense of coming first alphabetically
matrenka [14]

Answer:

The function written in python is as follows

def min(str1,str2):

     if str1 < str2:

           return str1

     else:

           return str2

Step-by-step explanation:

This line defines the function min, along with two parameters str1 and str2

def min(str1,str2):

This line checks if str1 is less than str2

if str1 < str2:

If yes, the function returns str1

 return str1

If otherwise,

else:

The function returns str2

 return str2

Take for instance

str1 = "abc"

str2 = "cba"

The function will return str1 because str1 is less than str2 in the sense that the first letter of str1 (a) is less than the first letter of str2 (c)

7 0
3 years ago
Roy used 1/4 of his money on 3 pens and 6 notebooks. The cost of each pen is 3 times the cost of each notebook. He bought some m
cestrela7 [59]
<h3>Answer:  13 pens</h3>

=========================================================

Explanation:

Roy spends 1/4 of his money on 3 pens and 6 notebooks. That means 3/4 of it is leftover.

2/3 of 3/4 = (2/3)*(3/4) = 1/2 of his money is spent on buying some unknown number of additional pens. We'll come back to this later.

---------------

In terms of cost,

1 pen = 3 notebooks

which is another way of saying 1 pen is the same price as 3 notebooks.

Multiply both sides by 2 to get

2 pens = 6 notebooks

Therefore, saying "3 pens + 6 notebooks" is the same as "3 pens + 2 pens = 5 pens" when just thinking about costs.

---------------

In short, Roy buying 3 pens and 6 notebooks is the same as him buying 5 pens. He spends 1/4 = 25% of his money on getting these 5 pens.

Multiply those two values by 2 to find that 50% = 1/2 of his money would allow him to get 10 pens.

--------------

Recall that at the end of the first section, we concluded that Roy spent 1/2 of his money on buying those unknown additional number of pens. Then the previous section mentioned that 1/2 of his money gets him 10 pens. Therefore, he must have bought 10 additional pens on top of the original 3 mentioned in the instructions.

Overall, he purchased 3+10 = 13 pens

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2 years ago
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aleksandr82 [10.1K]

Answer:. No

Step-by-step explanation:

Explanation:

The answer is NO because, mostly, there is always a variability in

the data used in answering statisticall questions. As in the question above, no variability

because Megan is taller than Jim or she is not taller than jim.

Thus, the question is not statistical in nature.

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293 tens and 4 ones

<em>Explanation:
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3 0
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