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Flauer [41]
4 years ago
11

A tank can hold 50 liters of water. At present, it is only 30% full. How many liters of water shall I put in the tank, so that i

s it 50% full?
Mathematics
1 answer:
damaskus [11]4 years ago
5 0

Calculate how many liters you need to be half full:

50 liters x 50% = 50 x 0.5 = 25 liters to be half filled.

Calculate how many liters are in the tank now:

50 x 0.30 = 15 liters

Now subtract to find how many more liters are needed:

25 - 15 = 10 more liters.

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A cognitive psychologist wants to know whether memory performance is changed by old age. She randomly selects 7 elderly individu
defon

Answer:

z = \frac{418.7-465.6}{\frac{53.6}{\sqrt{7}}}= -2.340

Now we can calculate the p value with the following probability

p_v =2*P(z

If we use the commonly significance level of 0.05 we see that the p value is lower than these values we can conclude that the true mean is different from the value of 465.6 at 5% of significance

Step-by-step explanation:

Data provided

\bar X=418.7 represent the mean score on the standardized memory test

\sigma=53.6 represent the population standard deviation

n=7 sample size    

\mu_o =465.6 represent the value that we want to verify

z would represent the statistic

p_v represent the p value

System of hypothesis

We are interested to check if the memory performance for elderly individuals differs from that of the general population (mean different from 465.6), the system of hypothesis are then:

Null hypothesis:\mu = 465.6    

Alternative hypothesis:\mu \neq 465.6    

Since we know the population deviation we can use the z statistic from the z test for the true mean:

z =\frac{\bar X -\mu}{\frac{\sigma}{\sqrt{n}}} (1)    

Replacing the info given we got:

z = \frac{418.7-465.6}{\frac{53.6}{\sqrt{7}}}= -2.340

Now we can calculate the p value with the following probability

p_v =2*P(z

If we use the commonly significance level of 0.05 we see that the p value is lower than these values we can conclude that the true mean is different from the value of 465.6 at 5% of significance

6 0
4 years ago
Find the range and the first and third quartiles for the data set 45,42,86,13,74,47,46
Lesechka [4]

The range = highest value - lowest = 86 - 13 = 73.

arrange in order:-

13 42 45 46 47 74 86

median = 46

First quartile = (42 + 45) / 2 = 43.5

third quartile = (74 - 47) / 2 = 60.5

6 0
3 years ago
Find the measure of the complement of an angle that measures 64°.
77julia77 [94]
90 - 64 = ? ...................

6 0
3 years ago
What fractions is equivalent to 0.6​
viva [34]

Answer:

3/5

Step-by-step explanation:

5 0
3 years ago
Read 2 more answers
Please answer this question below.
Katarina [22]
In a theatre room, there are 4 rows of  chairs. There are 4 columns of chairs. How many chairs are there in the theatre room?

4x4=16 

There are 16 chairs in the theatre room.
5 0
4 years ago
Read 2 more answers
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