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Umnica [9.8K]
3 years ago
8

It is reported that the wild gorilla population has declined by 70% over the last 10 years. There are now 4,000 gorillas left in

the wild. To the nearest thousand, how many gorillas were there 10 years ago?
Mathematics
1 answer:
Cloud [144]3 years ago
3 0
I will try to get back to you a little later
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What is 29.5 times 1.3
tatiyna

i belive the answer is 38.35

5 0
3 years ago
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Dream Studio offers 5 music lessons for $60. Fox Studio offers 8 music lessons for $72. What is the cost per lesson at each stud
ehidna [41]
Answer:
Dream Studio offers music lessons at $12 per lesson. Fox Studio offers music lessons at $9 per lesson. The better deal here would be Fox Studio. This is because Fox Studio offers cheaper lessons. For eight lessons at Dream Studio it costs $96, where as eight lessons at Fox Studio costs only $72.


Explanation:
Step 1 - Find the cost per lesson at Dream Studio

60 / 5 = 12

So, $12 per music lesson at Dream Studio.

Step 2 - Find the cost per lesson at Fox Studio

72 / 8 = 9

So, $9 per music lesson at Fox Studio.

Step 3 - Find out which offers a better deal

•Dream Studio = $96 for eight music lessons
• Fox Studio = $72 for eight music lessons
6 0
2 years ago
Explain why the question "How many colors are there in the United States flag?" is NOT a statistical question.
Shtirlitz [24]
The answer is d (all answers are pretty true)
3 0
3 years ago
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Various problems with data collection can cause some observations to be missing. Suppose a data set has 20 cases. Here are the v
mr Goodwill [35]

Answer:

a) Mean= 15, standard deviation= 5.1575

b) Mean= 15, standard deviation= 3.6469

c) See below

Step-by-step explanation:

(a) Compute the mean and standard deviation for the 10 cases for which x is not missing.

The mean using the ten known values is

\bar x=\frac{17+6+12+14+20+23+9+12+16+21}{10}=15

The standard deviation is

\small s=\sqrt{\frac{(17-15)^2+(6-15)^2+(12-15)^2+(14-15)^2+(20-15)^2+(23-15)^2+(9-15)^2+(12-15)^2+(16-15)^2+(21-15)^2}{10}}=5.1575

(b) Create a new data set with 20 cases by using imputation where you set the values for the 10 missing cases equal to the mean that you computed in the previous part. Compute the mean and standard deviation for this new data set with 20 cases.

The new data set would be

17, 6, 12, 14, 20, 23, 9, 12, 16, 21, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15

The new mean for this set of values would be then

\bar x=\frac{\displaystyle\sum_{i=1}^{20}x_i}{20}=15

The new standard deviation is now

s=\sqrt{\frac{\displaystyle\sum_{i=1}^{20}(x_i-\bar x)^2}{20}}=3.6469

(c) Summarize what you have learned about the possible effects of this type of imputation on the mean and the standard deviation.

Obviously, this way of imputation is somewhat arbitrary and will produce a set of data undoubtedly skewed.  

It could possibly be a sensible way of imputing data if the amount of missing data is very little compared to the whole set, for example one or two data in a set of 100, but in this case we have 50% of missing data and it makes no sense this procedure.

4 0
3 years ago
Prove each of these identities.
Stella [2.4K]

Answer:

Identity (a) can be re-written as

sec x\ cosec x  - cot x = tan x

which we already proven in another question, while for idenity (b)

(A)\frac 1 {sin x} -sin x = cos x \frac{cos x}{sin x}\\\\(B)\frac {1-sin^2x}{sin x} = \frac {cos^2x} {sin x} \\\\(C) \frac {cos^2x}{sin x} =\frac {cos^2x} {sin x}

step A is simply expressing each function in terms of sine and cosine.

step B is adding the terms on the LHS while multiplying the one on RHS.

step C is replacing the term on the numerator with the equivalent from the pithagorean identity cos^2x  + sin^2x = 1

8 0
2 years ago
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