Answer:
Step-by-step explanation:
Answer:
Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Solution to the problem
Let X the random variable that represent the scores of a population, and for this case we know the distribution for X is given by:
Where
and
We are interested on this probability
And the best way to solve this problem is using the normal standard distribution and the z score given by:
If we apply this formula to our probability we got this:
And we can find this probability using the normal standard table or excel and we got:
Answer:
large = 18 3/4 = 18.75
small = 13/2 = 6 1/2 = 6.5
Step-by-step explanation:
Let l = the weight of large boxes
s = weight of small boxes
2 large and 3 small weights 57
2l+3s = 57
6 large and 5 small wights 145
6l+5s = 145
Multiply the first equation by 3
3(2l+3s) = 57*3
6l +9s =171
Subtract the second equation
6l +9s =171
-6l -5s = -145
-----------------------
4s =26
Divide each side by 4
4s/4 = 26/4
s = 26/4 = 13/2
Substitute this into the first equation
2l +3s = 57
2l + 3(13/2) =57
Multiply by 2 to get rid of the fractions
2(2l + 3(13/2)) =57*2
4l + 39 = 114
Subtract 39 from each side
4l +39-39 = 114-39
4l =75
Divide by 4
4l/4 = 75/4
l = 75/4 = 18 3/4
Answer:
13
Step-by-step explanation:
because a is the missing number. Well, 21 minus or - 8 is equal to 13.