BCSL-044 SOLVED ASSIGNMENT 2017-18 FOR IGNOU BCA 4th SEMESTER

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IGNOU BCA 4th Semester Solved Assignment

BCSL-044 STATISTICAL TECHNIQUES LAB

QUESTIONS SOLVED IN ASSIGNMENT

1. A LED light producer tested the life of 30 samples. This data is given in the following table. Perform the tasks given in (i) to (iv) on the data given below using a spreadsheet package:
   

   LED light life (in hrs)

   38005	40000	35093	33985	24987	34899	44955	34888	33908	34098
   27890	23009	34098	45008	45898	24898	30002	34526	41000	23989
   34567	23456	43211	54123	12584	36547	14569	321458	25478	36541
   41258	25478	26987	35896	39851	48015	41101	37097	41203	15874
   31000	24584	41023	36214	39201	37258	34589	27015	29654	28622

   1. Find the minimum and maximum LED light life using spreadsheet formula.
   2. Create 10 classes with suitable class intervals and create the frequency distribution. You must use Array formula.
   3. Find the percentage of LED lights which have less than mean life.
   4. Draw the histogram for the data above. Also try to relate it to normal distribution curve.
2. Perform the following tasks using a spreadsheet (you must either enter necessary formula that are required to calculate the value or you may use spreadsheet function for the same):
   1. Find the value of t for the give value of degree of freedom and significance level (alpha):
      

      Degree of freedom	alpha value
      12	0.05
      10	0.01

   2. A company manufactures a type of USB ports which should be 12 mm wide. A sample of 200 such USB ports were taken out of a lot consisting of 50000 ports. The mean sample width was found to be 11.95 mm having a standard deviation of 0.11 mm. Assuming confidence level of 95%, will you accept the USB lot. Justify your answer. Make suitable assumption, if any.
3. A hypothetical petrol pump is equipped with a test measure of 2 litres. A person can use this measure to verify, if s/he has got the right quantity of petrol. It has four filling machine namely A, B, C and D. Every day four samples are taken from every filling machine. The findings are given in the following table:
   

   Data of filling machines while measuring 2 litres (in litres)

   Sample	Manufacturer
   	A	B	C	D
   1	2.01	1.89	2.11	1.93
   2	2.02	1.87	2.01	1.93
   3	1.99	2.02	2.09	1.89
   4	1.98	1.97	2.01	2.00

   Perform an ANOVA using any software to test (at 5% level) whether all the four filling machines are giving correct amount of petrol. Make suitable assumptions, if any.

4. Rainfall of first 15 days of July is recorded in the following table. Use spreadsheet software to find the moving averages for the length of 3 and 5.
   

   Day	Rainfall (in mm)
   1	15
   2	25
   3	1
   4	0
   5	10
   6	19
   7	30
   8	2
   9	5
   10	22
   11	6
   12	5
   13	4
   14	16
   15	45

5. A company packs flour in sealed packs of 10 kgs. It measures the weight of 5 bags randomly; this measurement is repeated five times in each day. Calculate the control limits for mean and range, and plot the control charts using any statistical software. Make suitable assumptions, if any.
   

   The Data is given in following tables

   Sample Days	The weight of bag (kgs)
   1	10.050	9.990	10.175	10.089	10.005
   2	10.205	10.045	10.099	9.999	9.975
   3	10.153	10.001	10.500	9.979	9.898
   4	9.990	9.997	10.050	10.069	10.075
   5	10.973	11.045	11.025	11.022	10.999

   (Please take the suitable values of d2 , d3, d4 , A2 and other variables.)

6. An Umbrella manufacturing company records the sale of Umbrella units in different months as given in the following table. Fit a trend line using any statistical software to this sales data. Make suitable assumptions.
   

   Month	Mar	Apr	May	June	Jul	Aug	Sept
   Sales of Umbrella (Units)	500	1000	3000	7000	5000	2000	400

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