Answer:
About 3 years Speedy Jet printers be guaranteed.
Step-by-step explanation:
Given : Quality control studies for Speedy Jet Computer Printers show the lifetime of the printer follows a normal distribution with
mean
and standard deviation 
If the company wishes to replace no more than 10% of the printers.
To find : How long should Speedy Jet printers be guaranteed ?
Solution :
Using Z- table,
Z value corresponding to 10% or 0.10 = -1.28.
Applying z-score formula,

The value of x is given by,

Substitute the values,



So, approx 3 years.
Therefore, About 3 years Speedy Jet printers be guaranteed.
Answer:
0.999
Step-by-step explanation:
At least 1 correct means, 1 correct, 2 correct, 3 correct ... until 10 correct. That would be a long process to calculate.
<em>Instead we use the complement rule to calculate.</em>
<em>
</em>
<em />
<em>So we need to find P(x<1). So this is getting 0 answers correct, or 10 incorrect.</em>
<em />
In true false question, probablity of correct is 1/2 and incorrect is 1/2, hence,
Probability of 10 incorrect is (1/2)^10
Thus,

So the answer is 0.999 (rounded to nearest thousandth)
Answer:
Standard deviation gets smaller
Step-by-step explanation:
No. of students = 45
The class had an average of 56 words per minute (WPM) with a standard deviation of 7 WPM.

The teacher realized that the data from one student who typed 55 WPM was not entered.
So, new sum = 2520+55
New sum =2575
So, new mean =
New mean =57.22
Standard deviation is the measure of distance between observation and mean
So, if number gets closer to mean , Standard deviation gets smaller . if the numbers get bigger , Standard deviation gets bigger.
Since 55 is closer to 57.22
So, Standard deviation gets smaller
1 kg = 1000 grams
? kg = 1575 grams
1.575 kg = 1575 grams
1,575 grams is 1.575 kilograms.