Answer:
[tex] x = 35-4-5-3-5-4-4=10[/tex]
So then the value for Saturday should be equal or higher to 10 servings per day in order to have an average of 5 or higher.
Step-by-step explanation:
First we can begin finding the original average for the first 6 days of the week. We assume that the week start at Sunday, and we have data for Sunday, Monday, Tuesday, Wednesday, Thrusday, Friday. And we can find the average like this:
[tex]\bar X_i =\frac{4+5+3+5+4+4}{6}=4.167[/tex]
And for this case we have the original average under the goal of 5, so we need to find a value x, such that the final average taking in count the 7 days of the week would be 5.
[tex]\bar X_f = \frac{4+5+3+5+4+4+x}{7}=5[/tex]
So we can nultiply both sides by 7 and we got:
[tex]4+5+3+5+4+4+x = 35[/tex]
And then solving for x we got:
[tex] x = 35-4-5-3-5-4-4=10[/tex]
So then the value for Saturday should be equal or higher to 10 servings per day in order to have an average of 5 or higher.