00:01
Sample size for questions 1 to 4, so number of students is 90.
00:09
We have 5 different weight classes, 40 to 52, 53 to 62, 66 to 78, 79 to 91, and 92 to 104.
00:36
For okay okay so we've got 3 23 38 we've got something blank here the last one's 18 so we need to find what's in this blank area first so we need to sum up 3 23 38 and 18 which gives 82 because we have a sample size of 90 the last one's going to fill in as 8 okay perfect with that in mind now we can actually fill in the gap here so question one a is uh a is going to be our answer so i'll write this more clearly q1 a 8 q2 what is the class mark of the fourth class class mark essentially means the midpoint so we're looking at the fourth class which if we if we go down this column this is first the second this is the third the fourth and the fifth so we're looking at this so what's the average of oh sorry what's the midpoint between 79 and 92 so we do 92 plus 79 9 over 2, which equals a, which is 85, so 85 a.
02:24
Next we need to do q3, which asks us, where's the cumulative relative frequency of the fourth class? so we want to know what's 8 over 90 essentially as a percentage or as a decimal.
02:39
So 8 over 90 is 0.
02:42
0 .08 8, etc.
02:50
Which rounds to 0.
02:53
089 which is b.
03:00
Okay so q4 we have estimate the percentage of the students whose weights at most 878.
03:10
So we need to essentially accumulate all of these so and take as a percentage so this plus this plus this.
03:21
So we get 3 plus 23 plus 38 divided by 80 times by 100.
03:38
64 divided by so it should be 90, not 80, there are 90 students times by 100 gives us our percentage but we don't actually need 100 here i don't believe, oh wait we do, and we get 71 .1 % which is out of the options given, a 71 .11 % okay, next we need to do completely different parts of this question.
04:13
Question 5, regarding the sample, 3 .4, 2 .5, 4 .8, 2 .9, 2 .8, 2 .5.
04:25
So we've got 1st, 2nd, 3rd, 4th, 6th...