Statistics and Probability Answers

1.     Explain how research can be classified on the basis of (10 Marks):

a) Purpose    b) Method

2. Explain and distinguish how validity and reliability can be established between quantitative research and qualitative research (10 Marks)

3. Using examples, explain and distinguish between a theoretical framework and a conceptual framework in research (10 Marks)

4. Using examples, explain how different research designs determine different sampling methods (10 Marks)

5.     Citing examples, discuss the key unique features of social science research in distinction from the pure/applied sciences (10 Marks)

Use the z-table to find the area under the normal curve that is located between z=0 and each of the following.

AREA

1.z=0.56

2.z=1.32

3.z=1.05

4.z=-2.18

5.z=2.58

the central limit theorem is of assistance for the sampling distribution of

1.The mean selling price of new homes in a small town over a year was $115,000. The population standard deviation was $25,000. A random sample of 100 new home sales from this city was taken.

a. What is the probability that the sample mean selling price was more than $112,000? (1)

b. What is the probability that the sample mean selling price was between $110,000 and $120,000? (1)

c. What is the probability that the sample mean selling price was between $114,500 and $115,500? (1)

2. According to a survey, only 18% of customers who visited the web site of a major retail store made a purchase. Random samples of size 45 are selected.

a. What is the mean of all the sample proportions of customers who will make a purchase after visiting the web site? (1)

b. What is the standard deviation of all the sample proportions of customers who will make a purchase after visiting the web site?

c. What proportion of all possible samples will have between 20% and 30% of customers who will make a purchase after visiting the web site? (1)

d. What proportion of all possible samples will have less than 15% of customers who will make a purchase after visiting the web site? (1)

e. 90% of the samples will have less than what percentage of customers who will make a purchase after visiting the web site? (1)

3. Assume that house prices in a neighborhood are normally distributed with a standard deviation of $20,000. A random sample of 16 observations is taken. What is the probability that the sample mean differs from the population mean by more than $4,000? (1)

4. A manufacturer of power tools claims that the mean amount of time required to assemble their top-of-the-line table saw is 80 minutes with a standard deviation of 20 minutes. Suppose a random sample of 64 purchasers of this table saw is taken. What is the probability that the sample mean will be between 78 and 85 minutes? (1)

Based on what you searched regarding stratified random sampling,complete the following table

Number of COVID Cases in the 1st District of Nueva Ecija as of October 21, 2020

Municipalities no.of patients Proportion

— Cuyapo          15

— Nampicuan      0

— Guimba          24

— Licab            6

— Quezon          11

— Sto. Domingo   15  

— Zaragoza        5

— Aliaga           16

— Talavera         24 

TOTALS      N= 116         100%

Source: Nueva EcijaTV48

Give the value of proportion and Sample

A wholessale disstribution of a tablet compresion machine finds that the annual demand for the product is normal distribution with mean 140 and standared deviation of 15. ifhe orders only once in a year. What quantity should be ordered to ensure that there is only 5% chance of running short

 A <b><i>wholesale</i></b> <b><i>distribution</i></b> of a tablet <b><i>compression</i></b> machine finds that the annual demand for the product is normal distribution with mean 140 and standared deviation of 15. ifhe orders only once in a year. What quantity should be ordered to ensure that there is only 5% chance of running short

The given table shows the rainfall of Gujarat Region. Forecast the rainfall using Exponential Smoothing. Use Alpha =0.2, 0.5 and 0.8. Data is available from 1997 to 2016, use this series for the calculation and forecast the rainfall for the year 2017. To know, the extent the prediction is correct the actual rainfall for 2017 (1024.4 millimeters) is provided. Find out which alpha values among the three suggestions are near to accurate value?

SUBDIVISION

YEAR

ANNUAL (in MM)

Gujarat Region

1997

1068.9

Gujarat Region

1998

1070

Gujarat Region

1999

568.4

Gujarat Region

2000

550.6

Gujarat Region

2001

849

Gujarat Region

2002

637.2

Gujarat Region

2003

1160.3

Gujarat Region

2004

1005.8

Gujarat Region

2005

1316.4

Gujarat Region

2006

1478

Gujarat Region

2007

1178.9

Gujarat Region

2008

911.1

Gujarat Region

2009

641.6

Gujarat Region

2010

1088.7

Gujarat Region

2011

890.5

Gujarat Region

2012

714

Gujarat Region

2013

1118.6

Gujarat Region

2014

705.7

Gujarat Region

2015

622.9

Gujarat Region

2016

764.9

nine students obtained the following percentage of marks in the college internal test (x) and in the final university examination (y). Find the correlation coefficient between the marks of the two test. x 51 63 73 46 50 60 47 36 60 y 49 72 74 45 58 66 50 30 35

find the area under the curve and between z=0.64 and z=2.23