Statistics and Probability: Analyzing Data from Various Sources - Prof. Couso, Exámenes de Idioma Inglés

¡Descarga Statistics and Probability: Analyzing Data from Various Sources - Prof. Couso y más Exámenes en PDF de Idioma Inglés solo en Docsity! Intr. a la Estad́ıstica 2010-2011 Fac. Comercio, Turismo y CC. Sociales Jovellanos 17 enero 2011 1. The price of a product has fluctuated widely in the last 3 years: From 2007 to 2008 it has raised by 4%. From 2008 to 2009 it has raised by 3%. From 2009 to 2010 it has fallen by 10%. Calculate the average rise rate in the last 3 years. Is it positive or negative? 2. The following double-entry frequency table displays the joint distribution of the the level of satisfaction with a service (X) in a scale from 1 (totally dissatisfied) to 5 (totally satisfied) and the gender (Y ). The bar diagram displays the marginal distribution of variable X in the same sample. X \ Y man woman 1 1 6 2 1 4 3 5 1 4 3 1 5 5 3 Bar diagram 0 1 2 3 4 5 6 7 8 9 1 2 3 4 5 Satisfaction level fr e q u e n ci e s The values of some statistics for Y (satisfaction level) are provided below: Arithmetic mean Median Variance Men ? 4 ? Women 2.4 2 2.37 (a) How many people have been surveyed? (b) What percentage of the people surveyed have expressed a satisfaction level lower than or equal to 3? (c) Out of the total number of women surveyed, what percentage of them have ex- pressed a satisfaction level lower than or equal to 3? (d) Determine the frequency table for the satisfaction level on the sub-sample of men. Based on this table, calculate the mean and the variance of the satisfaction level over the sub-sample of men. (e) Which group has provided more homogeneous responses, the group of men or the group of women? (f) Is 0 a possible value for c (contingency coefficient) in this example? And -0.8? Justify your answers, without performing any calculation. 3. The following table and scatter plot provide data about the income (X, in euros/month) and expenditure on food (Y, in euros/month) on a sample of 12 families.