Answer:
January had a higher z-score for sales on the 15th, and the value of that z-score was of 0.5.
Step-by-step explanation:
z-score:
In a set with mean 
and standard deviation 
, the z-score of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
January:
The mean daily sales for January was $300 with a standard deviation of $20. On the 15th of January, the shop sold $310 of yogurt. This means, respectively, that 
. So
February:
The mean daily sales for February was $320 with a standard deviation of $50. On the 15th of February, the shop sold $340 of yogurt. This means, respectively, that 
. So
January had a higher z-score for sales on the 15th, and the value of that z-score was of 0.5.
Answer: <u>Last option</u>
Step-by-step explanation:
The z-scores give us information about how many standard deviations from the mean the data are. This difference can be negative, if the data are n deviations to the left of the mean, or it can be positive if the data are n deviations to the right of the mean.
To calculate the Z scores, we calculate the difference between the value of the data and the mean and then divide this difference by the standard deviation.
so
.
Where x is the value of the data, μ is the mean and σ is the standard deviation
In this case
:
μ = 12 $/h
= 2 $/h
We need to calculate the Z-scores for 
and 
Then for :
.
Then for :
.
Therefore the answer is:
Answer:
We use negative values for the money Arleen spends.
a) We determine the change to the value on her gift card:
4(-35)+(-9)= -140+(-9)=-149
b) We determine the amount on money she has left on the gift card after renting the tiller and buying the rake:
200+(-149)=51
Since she has got $51 on her gift card and a wheelbarrow is $50 she is able to buy it:
51>50
RESULT
a) -$149 less b) yes
Step-by-step explanation:
