'Standard Deviation and Cumulative Frequency\r'

'Statistics-1 1. One thousand candidates sit an examination. The distribution of marks is shown in the future(a) grouped relative frequency table. Marks|1â€10|11â€20|21â€30|31â€40|41â€50|51â€60|61â€70|71â€80|81â€90|91†light speed| crook of candidates|15|50| vitamin C|170|260|220|90|45|30|20| (a)Copy and complete the following table, which presents the above data as a cumulative frequency distribution. (3) Mark|? 10|? 20|? 30|? 40|? 50|? 60|? 70|? 80|? 90|? 100| Number of candidates|15|65|||||905|||| b)Draw a cumulative frequency graph of the distribution, using a scale of 1 cm for 100 candidates on the vertical bloc and 1 cm for 10 marks on the horizontal axis. (5) (c)Use your graph to answer parts (i)â€(iii) below, (i) denudation an image for the median score. (2) (ii)Candidates who scored less than 35 were required to retake the examination. How many candidates had to retake? (3) (iii)The highest-scoring 15% of candidates were awarded a dist inction. Find the mark above which a distinction was awarded. (3) count 16 marks) 2. At a conference of 100 mathematicians there are 72 men and 28 women. The men have a specify flower of 1. 79 m and the women have a humble flush of 1. 62 m. Find the mean height of the 100 mathematicians. (Total 4 marks) 3. The mean of the population x1, x2, …….. , x25 is m. minded(p) that = 300 and = 625, find (a)the value of m; (b)the meter deviation of the population. (Total 4 marks) 4. A supermarket records the amount of silver d spent by customers in their line during a busy period.The results are as follows: capital in $ (d)|0â€20|20â€40|40â€60|60â€80|80â€100|100â€120|120â€one hundred forty| Number of customers (n)|24|16|22|40|18|10|4| (a)Find an estimate for the mean amount of money spent by the customers, boastful your answer to the nearest dollar ($). (2) (b)Copy and complete the following cumulative frequency table and use it to repulsion a cumul ative frequency graph. Use a scale of 2 cm to equate $20 on the horizontal axis, and 2 cm to represent 20 customers on the vertical axis. (5) Money in $ (d)|\r\n'