factor: Multiply SE of sample mean by fpc to make the correction ------------------------------------------------- Independent samples of same population with same standard deviation (variances are equal). Confidence interval: df for t-multiple is (df1 + df2)‚ or (n1 – 1) + (n2 - 1) Pooled estimate of common standard deviation: SE of difference between two sample means ------------------------------------------------- Confidence interval for differences in sample means when variance is
Premium Normal distribution Variance Standard deviation
the sample is expected Cost/operational concerns Simple random sampling [edit] Main article: Simple random sampling In a simple random sample (SRS) of a given size‚ all such subsets of the frame are given an equal probability. Furthermore‚ any given pair of elements has the same chance of selection as any other such pair (and similarly for triples‚ and so on). This minimises bias and simplifies analysis of results. In particular‚ the variance between individual results within the sample is a
Premium Sampling Sample size
Brief Introduction: AJ Davis is a department store chain‚ which has many credit customers and want to find out more information about these customers. AJ Davis has complied a sample of 50 credit customers with data selected in the following variables: Location‚ Income (in $1‚000’s)‚ Size (Number of people living in the household)‚ Years (number of years the customer has lived in the current location)‚ and Credit Balance (customers current credit card balance on the store’s credit car‚ in $)
Premium Statistical hypothesis testing Statistics Statistical inference
Chapter 1 INTRODUCTION Around the world for centuries‚ the buying and selling of food has been transacted in public market places open to all. In the broadcast definition‚ a public market is any place where buyers and sellers of food meet regularly for trade. From simple gatherings of farmers at country cross roads to 19th century cathedrals of glass and iron‚ market were once a primary channel of food distribution in cities both in the Philippines and abroad. Where food is concerned‚ few
Premium Sewage treatment Sampling Markets
and a need for challenge and women more likely to exhibit external locus of control and need for affiliation (belonging to a group). High Internal females earned more than external women. The fact there is a large sample size of 2600 means the findings are reliable‚ good sample size. However it can be argued that there is a potential cultural bias as the data was only taken from Russian employees. When Asch debriefed his participants‚ he found a common factor of confidence in the people who
Premium Sample size Social psychology Motivation
standard error of the mean for each sampling situation (assuming a normal population). What happens to the standard error each time you quadruple the sample size? a. σ = 36‚ n = 9 36 √9=12 b. σ = 36‚ n = 36 36 √36=6 c. σ = 36‚ n = 144 =3 formula SE= σ √n #2. A sample was taken of 36 people attending a school with an annual average tuition of $3800 and the population standard deviation of $620. Find the 95% confidence
Premium Normal distribution Sample size Standard deviation
The following report presents a detailed statistical analysis of AJ DAVIS department store customers. Data was collected from a sample of 50 AJ DAVIS credit customers for the purpose of learning more about the customers of AJ DAVIS. The first variable considered is Location‚ a categorical variable. The three subcategories are Urban‚ Suburban and Rural. The frequency distribution and pie chart are included. Measures of central tendency and descriptive statistics are not calculated due to the
Premium Statistical hypothesis testing Statistics Arithmetic mean
b. t distribution c. the mean of the sample d. the mean of the population Answer: b 2. As the number of degrees of freedom for a t distribution increases‚ the difference between the t distribution and the standard normal distribution a. becomes larger b. becomes smaller c. stays the same d. None of these alternatives is correct. Answer: b 3. For the interval estimation of ( when ( is known and the sample is large‚ the proper distribution to use is a
Premium Normal distribution Confidence interval Standard deviation
in foil packs were allowed to warm to room temperature before opening to prevent condensation. Once opened‚ the micro-titration strips were stored at 2-8°C until use. All samples and reagents were kept at room temperature (20 - 25 °C) before and during the testing‚ but were returned to 2 – 8°C immediately after use. For each sample‚ a new pipette tip was used and precautionary measures were taken never to touch the pipette tip to the bottom of the well. All the used materials were disposed off as bio-hazardous
Premium Sample size Sampling Confidence interval
proportion. b) Is finding an interval estimate an example of inferential or descriptive statistics? Explain. It is an interval estimate is an example of inferential statistics‚ as an estimate of the value of the population parameter is made based on sample statistics. c) An interval estimate (23.8‚ 30.6) is determined for the mean age of NSCC students. Identify the point estimate and the margin of error of the interval estimate. The point estimate=27.2 and the margin of error=3.4 d) The proportion
Premium Statistical inference Statistical hypothesis testing Confidence interval