Edexcel S1 - 15th June, 2016 [Exam Discussion]

well q4 was hard. Otherwise reckon I got 68/69+

boundaries for 100, 90, 80 UMS?

I think
71+ for 100
67+ for 90
56+ for 80

that is wrong. You time the 40 by your part d(i) and your 37 by part d(ii) and you get 33

Did anyone else say that the mean decreased?? I know you weren't supposed to use calculations but I did just to check my answer. The new baby was 3.43 but that means that the fx value is now (18x3.25) not (17x3.25) then divided by 51 instead of 50. In ungrouped data it would stay the same but I thought because it was grouped it'd decrease?? Think I've got it wrong!!

I said the median and mean were so close that there was just a slight skew, because it was so small it could be seen as symmetrical and normal distribution is okay

I've seen them accept both justified sides

Also, what was the effect of the new data on the PMCC for question 3?

I swear the mean stayed the same?????


Posted from TSR Mobile

I swear the mean stayed the same?????


Posted from TSR Mobile

well could you explain why its wrong?

yes 0.1 and 0.2 is wrong

While this may be a valid answer, the other parts of the question indicated that he was wrong. The question specifically asked for you to use your answers from b), c) and d) to come to a conclusion. b) showed that the median was not equal to the mean, c) showed that the standard deviation was not 0.65 and d) showed that the proportion of babies with weight below 3kg was not the same as the table. I think you'd still get the marks if you've given a valid explanation, just that the question said to take more than just the averages into account

only 2, dont stress

I said something along the lines of 'his suggestion is unreliable as the Median(Calculated from b.) was 3.47 which is greater than the mean (Proven from cii.) of 3.43. This means there is a slight negative skew. Part e) was calculated based on the assumption of nil skewness.'
I had thought about mentioning standard deviation but as it was calculated in part d) and the question explicitly asked for references to b, cii and e) prompted me exclude it from the answer.

I said something along the lines of 'his suggestion is unreliable as the Median(Calculated from b.) was 3.47 which is greater than the mean (Proven from cii.) of 3.43. This means there is a slight negative skew. Part e) was calculated based on the assumption of nil skewness.'
I had thought about mentioning standard deviation but as it was calculated in part d) and the question explicitly asked for references to b, cii and e) prompted me exclude it from the answer.