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What is the null and alternative hypothesis? Identify or explain in your own words.

What is the null and alternative hypothesis? Identify or explain in your own words.

MATLAB: An Introduction with Applications
MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
Problem 1P
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Please answer the following questions.

  1. What is the null and alternative hypothesis? Identify or explain in your own words.
Assignment Randomisation was undertaken by an independent agency, which produced and packaged the trial solutions. Allocation was on a 1:1 basis using computer generated random permuted blocks of 10.² The placebo and active trial solutions (5 ml each) were packaged in identical bottles. Each was labelled with a unique trial number and placed in a sealed trial box. Women were randomised when the attending midwife judged spontaneous vaginal delivery imminent, and the next consecutive trial box was opened. Outcome measures The primary outcome was pain during delivery, self reported before leaving the delivery suite and assessed on a 0-100 scale from 0 (no pain) to 100 (worst possible pain). The 16 secondary outcomes were: delivery pain by a four level ordered categorical assessment of severity and the adapted McGill pain questionnaire (short form) total score¹0; satisfaction with analgesia; second degree perineal trauma (including women who had an episiotomy); genital tract trauma and its management; feelings during delivery; overall rating of birth experience; perineal pain one week after delivery; resumption of intercourse by two months; dyspareunia by two months; maternal adjustment to motherhood¹3; and condition of the baby at birth. Nonresponders to questionnaires were sent a reminder letter after two weeks and a letter and additional questionnaire after four weeks. Midwives collected a sample of cord blood for ascertainment of lidocaine levels. They also completed a questionnaire on deliveries. We obtained data on sociodemographic characteristics and the acceptability of the intervention to women through a questionnaire given 6-8 days after delivery. Acceptability to 14 midwives was ascertained through semistructured interviews, the transcripts of which were subjected to a thematic analysis. Sample size In a pilot study carried out at the trial site, the levels of pain experienced by 67 women without epidural analgesia during spontaneous vaginal delivery were ascertained on the primary pain outcome, yielding a mean 65.3 (SD 25.7). We considered as clinically significant a reduction in pain during delivery of 0.5 standard deviations (13 scale points); 180-212 women were required to detect such a difference with 85%-90% power and a two sided 5% significance level, allowing conservatively for 20% attrition. Analysis We analysed the data using SPSS. The primary comparative analyses were carried out on an intention to treat basis, with data analysts blind to treatment group. We used regression analysis to compare the outcomes between groups. Secondary analyses also involved regression models: firstly, adjusting for variables that showed a potentially important imbalance at baseline; secondly, restricting analysis to those who received either spray fully in accordance with the protocol; and thirdly, including the relevant interaction to carry out a planned subgroup analysis according to whether or not it was the woman's first delivery. Perineal pain was the primary outcome. Before inspection of the data, we considered possible mechanisms by which the intervention might affect the primary outcome. As a consequence we identified perineal trauma as a secondary outcome of particular interest. The reason for this was that perineal pain could be closely related to perineal integrity. For example, reduced pain might be associated with increased perineal trauma if the birth was accelerated by the intervention. We therefore calculated the number needed to treat for perineal trauma, along with a 95% confidence interval. 14 Results Go to: Of the 2200 women delivering at the participating unit during the recruitment period, 680 were interested during their antenatal period in participating (fig 1). Of these, 66 became ineligible once in labour and three had been randomised but had ventouse assisted delivery, precluding use of the spray. These women were excluded from analyses because their primary outcomes could not have been influenced by the intervention and the decision on delivery method was independent of trial allocation. Consent was not sought in labour from a further 429 women, due primarily to admission in advanced labour or request for an epidural. All 185 women approached in labour provided consent and were randomised: 93 to lidocaine spray and 92 to placebo spray.
Transcribed Image Text:Assignment Randomisation was undertaken by an independent agency, which produced and packaged the trial solutions. Allocation was on a 1:1 basis using computer generated random permuted blocks of 10.² The placebo and active trial solutions (5 ml each) were packaged in identical bottles. Each was labelled with a unique trial number and placed in a sealed trial box. Women were randomised when the attending midwife judged spontaneous vaginal delivery imminent, and the next consecutive trial box was opened. Outcome measures The primary outcome was pain during delivery, self reported before leaving the delivery suite and assessed on a 0-100 scale from 0 (no pain) to 100 (worst possible pain). The 16 secondary outcomes were: delivery pain by a four level ordered categorical assessment of severity and the adapted McGill pain questionnaire (short form) total score¹0; satisfaction with analgesia; second degree perineal trauma (including women who had an episiotomy); genital tract trauma and its management; feelings during delivery; overall rating of birth experience; perineal pain one week after delivery; resumption of intercourse by two months; dyspareunia by two months; maternal adjustment to motherhood¹3; and condition of the baby at birth. Nonresponders to questionnaires were sent a reminder letter after two weeks and a letter and additional questionnaire after four weeks. Midwives collected a sample of cord blood for ascertainment of lidocaine levels. They also completed a questionnaire on deliveries. We obtained data on sociodemographic characteristics and the acceptability of the intervention to women through a questionnaire given 6-8 days after delivery. Acceptability to 14 midwives was ascertained through semistructured interviews, the transcripts of which were subjected to a thematic analysis. Sample size In a pilot study carried out at the trial site, the levels of pain experienced by 67 women without epidural analgesia during spontaneous vaginal delivery were ascertained on the primary pain outcome, yielding a mean 65.3 (SD 25.7). We considered as clinically significant a reduction in pain during delivery of 0.5 standard deviations (13 scale points); 180-212 women were required to detect such a difference with 85%-90% power and a two sided 5% significance level, allowing conservatively for 20% attrition. Analysis We analysed the data using SPSS. The primary comparative analyses were carried out on an intention to treat basis, with data analysts blind to treatment group. We used regression analysis to compare the outcomes between groups. Secondary analyses also involved regression models: firstly, adjusting for variables that showed a potentially important imbalance at baseline; secondly, restricting analysis to those who received either spray fully in accordance with the protocol; and thirdly, including the relevant interaction to carry out a planned subgroup analysis according to whether or not it was the woman's first delivery. Perineal pain was the primary outcome. Before inspection of the data, we considered possible mechanisms by which the intervention might affect the primary outcome. As a consequence we identified perineal trauma as a secondary outcome of particular interest. The reason for this was that perineal pain could be closely related to perineal integrity. For example, reduced pain might be associated with increased perineal trauma if the birth was accelerated by the intervention. We therefore calculated the number needed to treat for perineal trauma, along with a 95% confidence interval. 14 Results Go to: Of the 2200 women delivering at the participating unit during the recruitment period, 680 were interested during their antenatal period in participating (fig 1). Of these, 66 became ineligible once in labour and three had been randomised but had ventouse assisted delivery, precluding use of the spray. These women were excluded from analyses because their primary outcomes could not have been influenced by the intervention and the decision on delivery method was independent of trial allocation. Consent was not sought in labour from a further 429 women, due primarily to admission in advanced labour or request for an epidural. All 185 women approached in labour provided consent and were randomised: 93 to lidocaine spray and 92 to placebo spray.
Abstract Objectives To evaluate the effectiveness and acceptability of a lidocaine spray in reducing perineal pain during spontaneous vaginal delivery. Design Randomised controlled trial. Setting Consultant led obstetric unit. Go to: Participants 185 women who had a spontaneous vaginal delivery without epidural analgesia. Interventions Topically applied local anaesthetic spray (93 women) and placebo spray (92 women). Main outcome measure Primary outcome measure was pain during delivery (0-100 scale). The 16 secondary outcome measures included second degree perineal trauma during delivery, trauma of the genital tract, and dyspareunia by two months. Results Lidocaine spray did not reduce pain during spontaneous vaginal delivery: mean 77 and 72 on a scale of 0-100 in the lidocaine and placebo groups, respectively (difference between means 4.8, 95% confidence interval -1.7 to 11.2). Lidocaine spray may reduce genital tract trauma during delivery, in particular second degree perineal trauma. The intervention was highly acceptable to the women and midwives. Conclusions Although lidocaine spray applied to the perineum during spontaneous vaginal delivery did not reduce perineal pain, it was acceptable to both the women and the midwives. Trial registration Current controlled trials ISRCTN99732966. Introduction Go to: Numerous studies have been published on analgesia during labour Yet it is common for women having spontaneous vaginal delivery not to be offered analgesia for perineal pain during second stage labour. A national survey of UK midwifery practice found that midwives applied a variety of substances to the perineum to reduce pain, including lidocaine in a few cases. Although midwives considered these techniques to be effective, none has been rigorously evaluated. Moreover, many randomised trials of management of second stage labour, including analgesics, have not measured pain experienced by the mother.³4 Although care of the perineum has been extensively researched, studies have focused on preventing trauma, including episiotomy, rather than on reducing pain explicitly. We compared the effectiveness of a local anaesthetic spray with a placebo spray in reducing perineal pain in women having a spontaneous vaginal delivery. We also ascertained the views of the women and midwives on acceptability of the sprays. Participants and methods Trial interventions Go to: Between February 2003 and May 2004 midwives provided written and verbal information about the trial to potentially eligible women more than 30 weeks' pregnant who attended antenatal clinics in the area served by the participating hospital. The midwife placed a sticker on the maternity notes indicating whether the woman was ineligible, had declined participation in the trial, or had expressed an interest. Exclusion criteria during the antenatal period were multiple pregnancy; booked in for a caesarean section, instrumental delivery, or episiotomy; previous adverse reaction to a local anaesthetic; and insufficient English to provide consent or complete the study questionnaires. Exclusion criteria during the intrapartum period were pregnancy less than 37 weeks' gestation, epidural analgesia, non-cephalic presentation, and baby expected to require intensive neonatal care after delivery. Women who had expressed an interest in the trial were identified by hospital based midwives when they were admitted to hospital in labour or for induction of labour. After checking eligibility and obtaining written consent, the midwife asked a member of the medical staff to prescribe the trial solution. Before randomisation the attending midwife reconfirmed the woman's consent to participate. The active trial solution was formulated to equate to Xylocaine spray (AstraZeneca, Bedfordshire), omitting cosmetic ingredients. The active and placebo trial solutions were of similar appearance, consistency, and odour. Attending midwives were instructed to apply five sprays of the solution, each of 0.1 ml, to the woman's perineum and inside aspect of the labia once spontaneous birth was imminent. Spraying was to be suspended if the fetal head had advanced such that the dosage could not be completed before the midwife needed to prepare for delivery. The number of sprays administered was recorded, and the time between application and delivery was calculated. The five sprays were to be administered at least three minutes before delivery to have time to take effect.
Transcribed Image Text:Abstract Objectives To evaluate the effectiveness and acceptability of a lidocaine spray in reducing perineal pain during spontaneous vaginal delivery. Design Randomised controlled trial. Setting Consultant led obstetric unit. Go to: Participants 185 women who had a spontaneous vaginal delivery without epidural analgesia. Interventions Topically applied local anaesthetic spray (93 women) and placebo spray (92 women). Main outcome measure Primary outcome measure was pain during delivery (0-100 scale). The 16 secondary outcome measures included second degree perineal trauma during delivery, trauma of the genital tract, and dyspareunia by two months. Results Lidocaine spray did not reduce pain during spontaneous vaginal delivery: mean 77 and 72 on a scale of 0-100 in the lidocaine and placebo groups, respectively (difference between means 4.8, 95% confidence interval -1.7 to 11.2). Lidocaine spray may reduce genital tract trauma during delivery, in particular second degree perineal trauma. The intervention was highly acceptable to the women and midwives. Conclusions Although lidocaine spray applied to the perineum during spontaneous vaginal delivery did not reduce perineal pain, it was acceptable to both the women and the midwives. Trial registration Current controlled trials ISRCTN99732966. Introduction Go to: Numerous studies have been published on analgesia during labour Yet it is common for women having spontaneous vaginal delivery not to be offered analgesia for perineal pain during second stage labour. A national survey of UK midwifery practice found that midwives applied a variety of substances to the perineum to reduce pain, including lidocaine in a few cases. Although midwives considered these techniques to be effective, none has been rigorously evaluated. Moreover, many randomised trials of management of second stage labour, including analgesics, have not measured pain experienced by the mother.³4 Although care of the perineum has been extensively researched, studies have focused on preventing trauma, including episiotomy, rather than on reducing pain explicitly. We compared the effectiveness of a local anaesthetic spray with a placebo spray in reducing perineal pain in women having a spontaneous vaginal delivery. We also ascertained the views of the women and midwives on acceptability of the sprays. Participants and methods Trial interventions Go to: Between February 2003 and May 2004 midwives provided written and verbal information about the trial to potentially eligible women more than 30 weeks' pregnant who attended antenatal clinics in the area served by the participating hospital. The midwife placed a sticker on the maternity notes indicating whether the woman was ineligible, had declined participation in the trial, or had expressed an interest. Exclusion criteria during the antenatal period were multiple pregnancy; booked in for a caesarean section, instrumental delivery, or episiotomy; previous adverse reaction to a local anaesthetic; and insufficient English to provide consent or complete the study questionnaires. Exclusion criteria during the intrapartum period were pregnancy less than 37 weeks' gestation, epidural analgesia, non-cephalic presentation, and baby expected to require intensive neonatal care after delivery. Women who had expressed an interest in the trial were identified by hospital based midwives when they were admitted to hospital in labour or for induction of labour. After checking eligibility and obtaining written consent, the midwife asked a member of the medical staff to prescribe the trial solution. Before randomisation the attending midwife reconfirmed the woman's consent to participate. The active trial solution was formulated to equate to Xylocaine spray (AstraZeneca, Bedfordshire), omitting cosmetic ingredients. The active and placebo trial solutions were of similar appearance, consistency, and odour. Attending midwives were instructed to apply five sprays of the solution, each of 0.1 ml, to the woman's perineum and inside aspect of the labia once spontaneous birth was imminent. Spraying was to be suspended if the fetal head had advanced such that the dosage could not be completed before the midwife needed to prepare for delivery. The number of sprays administered was recorded, and the time between application and delivery was calculated. The five sprays were to be administered at least three minutes before delivery to have time to take effect.
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