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An automobile parts supplier wants to know how long car owners plan to keep their cars with them. A random sample of 20 car owners results in a standard deviation of 3.7 years. Find a 95% confidence interval for the variance and standard deviation. Assume that the variable is no..

Newton's laws of motion help us to analyse many kinds of motion. But the analysis is complicated, requiring details about the motion that we simply do not know. Long ago, people used to trade by only exchanging products when the concept of 'money' was yet to be introduced. Now w..

In physics, the word 'string' is used in a more general sense than what it normally denotes. In olden days, musical instruments employed strings of twisted intestines of animals, such as cat-gut. Nowadays, the strings of musical instruments like the veena, violin and guitar are made of metal wires...

. Similarly, developmental plans can be drawn on long term basis to attain success, if the population can be predicted for future period. Thus, study of population is useful to know many past, present and future issues of human society, national economy, environment and developm..

(i) Radioactive dating This gives us an approximate age of the rock or material containing the radioactive atoms. For e.g., A measurement of a fraction of uranium atom which have decayed into lead (by knowing the half life of uranium) tells us how old the rock is. (ii) Radiation from s..

Study of fossils is called palaenotolgy. Fossils are defined as preserved remains of a living organism that existed on earth a long time ago. Fossils are formed by the preservation of the remains of the organisms that existed in the earlier days. The dead bodies of the organisms are immed..

The kidney slowly deteriorates and stops functioning. The symptoms are water retention, acidosis, anaemia and increase in blood urea level. You have learnt how important the kidneys are for survival. Though kidney failure is not common, sometimes kidney infection, injury to kidneys or restricted b..

Knowing the electronic configuration, one can predict the period, which corresponds to the principal quantum number of the valence shell. The block of the element corresponds to the sub shell, which receives the last electron. The position of an element in the long form of the ..

. It is believed that when one travels through the hot Arabian deserts, one knows that there is an oasis close by when one hears the nightingale's lovely song. The reaper's song is compared to this as also to the cuckoo's song which announces the spring season in the remote islands of the..

. Lee Kuan Yew once said that Pillay compared with the best administrators in Britain or America. Indians know him for battling long and hard to launch a domestic airline in India in collaboration with the Tatas. --- Sunanda K. Datta Ray I Answer the following questions: 1) What..