The answer is: x = 261/133
Answer:
The 95 % confidence intervals (653.3 , 657.0) for the population mean test score
Step-by-step explanation:
Given school districts n = 420
The average score (Population mean) μ = 655.2
and standard deviation σ = 19.1
The 95% of confidence intervals μ± 1.96 σ/√n
The 95% of confidence intervals (μ- 1.96 σ/√n , μ+ 1.96 σ/√n)
The 95% of confidence intervals
( () ,
(655.2-1.826 , 655.2+1.826)
(653.3 , 657.0)
<u>Conclusion</u>:-
The 95 % confidence intervals (653.3 , 657.0) for the population mean test score
There are total 30 students in the piano class.
<h3>What is Ratio and Proportion ?</h3>
When a number can be divided by another number then they can be written as p : q , when two ratios can be equated using an equal sign then they are said to be in proportion.
It is given that the total number of girls is 40% of the total students
The ratio of total students to girls is 100 :40
= 10 :4
= 5 : 2
It is also given that in the total number of students 12 were girls
Let total students be x
Then the ratio is x : 12
As both the ratio are same and so can be equated and the proportion will be
5 : 2 = x : 12
5/2 = x /12
x = 30
Therefore there are total 30 students in the piano class.
To know more about Ratio and Proportion
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Answer:
is the simple form of 0.35.
i.e.
Step-by-step explanation:
Considering the decimal number
First lets convert it into a fraction
Multiply and divide by 10 for every number after the decimal point.
There are two digits to the right of the decimal point, therefore multiply and divide by 100.
Now reduce the fraction into a simple form
as
so
Therefore,
is the simple form of 0.35.
i.e.